chore(applicationsignals-alpha): remove B3 from default propagators (#35510)

### Issue # (if applicable)

N/A

### Reason for this change

B3 propagator currently drops trace state and baggage if it comes after either of the propagators responsible for propagating these informations. It provides no functionality and only blocks baggage in the current state.

This blocks certain AWS X-Ray features from being used effectively without asking users to override the default propagators

### Description of changes

- Removed B3 propagator from default propagators environment variable list

### Describe any new or updated permissions being added

N/A


### Description of how you validated changes

Confirmed with SME [wangzlei@](https://github.com/wangzlei) that B3 is no longer needed, as per owners listed in https://github.com/open-telemetry/opentelemetry-java-contrib/tree/main/aws-xray-propagator

Ran manual tests by deploying applications hosted in both EC2 and EKS with various propagator configurations that exclude B3 using Application Signals on Java and verified all Application Signals behaviour was functional and as expected.

Removed the B3 default propagator in ADOT Java that is applied in non-CDK environments and verified the Application Signals E2E tests passed: https://github.com/aws-observability/aws-otel-java-instrumentation/actions/runs/17587061009/job/49960543385

(Failed jobs are due to misconfiguration of unrelated actions)

### Checklist
- [x] My code adheres to the [CONTRIBUTING GUIDE](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md) and [DESIGN GUIDELINES](https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md)

----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

Author: majanjua-amzn

packages/@aws-cdk/aws-applicationsignals-alpha/lib/enablement/constants.ts

@@ -92,7 +92,7 @@ export class TraceExporting {
   /** Configuration for trace context propagation */
   public static readonly OTEL_PROPAGATORS = 'OTEL_PROPAGATORS';
   /** Supported propagation formats for Application Signals */
-  public static readonly OTEL_PROPAGATORS_APPLICATION_SIGNALS = 'tracecontext,baggage,b3,xray';
+  public static readonly OTEL_PROPAGATORS_APPLICATION_SIGNALS = 'tracecontext,baggage,xray';
 }
 
 /**

packages/@aws-cdk/aws-applicationsignals-alpha/test/ecs-sdk-instrumentation.test.ts

@@ -66,7 +66,7 @@ describe('application signals adot sdk agent integration', () => {
             },
             {
               Name: 'OTEL_PROPAGATORS',
-              Value: 'tracecontext,baggage,b3,xray',
+              Value: 'tracecontext,baggage,xray',
             },
             {
               Name: 'JAVA_TOOL_OPTIONS',
@@ -197,7 +197,7 @@ describe('application signals adot sdk agent integration', () => {
             },
             {
               Name: 'OTEL_PROPAGATORS',
-              Value: 'tracecontext,baggage,b3,xray',
+              Value: 'tracecontext,baggage,xray',
             },
             {
               Name: 'JAVA_TOOL_OPTIONS',
@@ -331,7 +331,7 @@ describe('application signals adot sdk agent integration', () => {
         },
         {
           Name: 'OTEL_PROPAGATORS',
-          Value: 'tracecontext,baggage,b3,xray',
+          Value: 'tracecontext,baggage,xray',
         },
         {
           Name: 'OTEL_PYTHON_DISTRO',
@@ -491,7 +491,7 @@ describe('application signals adot sdk agent integration', () => {
               },
               {
                 Name: 'OTEL_PROPAGATORS',
-                Value: 'tracecontext,baggage,b3,xray',
+                Value: 'tracecontext,baggage,xray',
               },
               {
                 Name: 'OTEL_DOTNET_DISTRO',
@@ -651,7 +651,7 @@ describe('application signals adot sdk agent integration', () => {
             },
             {
               Name: 'OTEL_PROPAGATORS',
-              Value: 'tracecontext,baggage,b3,xray',
+              Value: 'tracecontext,baggage,xray',
             },
             {
               Name: 'OTEL_DOTNET_DISTRO',
@@ -831,7 +831,7 @@ describe('application signals adot sdk agent integration', () => {
         },
         {
           Name: 'OTEL_PROPAGATORS',
-          Value: 'tracecontext,baggage,b3,xray',
+          Value: 'tracecontext,baggage,xray',
         },
         {
           Name: 'OTEL_SERVICE_NAME',
@@ -1001,7 +1001,7 @@ describe('application signals custom injector', () => {
             },
             {
               Name: 'OTEL_PROPAGATORS',
-              Value: 'tracecontext,baggage,b3,xray',
+              Value: 'tracecontext,baggage,xray',
             },
             {
               Name: 'JAVA_TOOL_OPTIONS',
@@ -1123,7 +1123,7 @@ describe('application signals custom injector', () => {
             },
             {
               Name: 'OTEL_PROPAGATORS',
-              Value: 'tracecontext,baggage,b3,xray',
+              Value: 'tracecontext,baggage,xray',
             },
             {
               Name: 'OTEL_PYTHON_DISTRO',
@@ -1254,7 +1254,7 @@ describe('application signals custom injector', () => {
             },
             {
               Name: 'OTEL_PROPAGATORS',
-              Value: 'tracecontext,baggage,b3,xray',
+              Value: 'tracecontext,baggage,xray',
             },
             {
               Name: 'OTEL_DOTNET_DISTRO',
@@ -1409,7 +1409,7 @@ describe('application signals custom injector', () => {
       },
       {
         Name: 'OTEL_PROPAGATORS',
-        Value: 'tracecontext,baggage,b3,xray',
+        Value: 'tracecontext,baggage,xray',
       },
       {
         Name: 'NODE_OPTIONS',

packages/@aws-cdk/aws-applicationsignals-alpha/test/integ.ecs-enablement-daemon.js.snapshot/ApplicationSignalsJavaApp-Daemon.template.json

@@ -46,7 +46,7 @@
        },
        {
         "Name": "OTEL_PROPAGATORS",
-        "Value": "tracecontext,baggage,b3,xray"
+        "Value": "tracecontext,baggage,xray"
        },
        {
         "Name": "JAVA_TOOL_OPTIONS",

packages/@aws-cdk/aws-applicationsignals-alpha/test/integ.ecs-enablement-daemon.js.snapshot/tree.json

@@ -59,7 +59,7 @@
        },
        {
         "Name": "OTEL_PROPAGATORS",
-        "Value": "tracecontext,baggage,b3,xray"
+        "Value": "tracecontext,baggage,xray"
        },
        {
         "Name": "OTEL_PYTHON_DISTRO",

packages/@aws-cdk/aws-applicationsignals-alpha/test/integ.ecs-enablement-replica.js.snapshot/ApplicationSignalsPythonApp-Replica.template.json

@@ -50,7 +50,7 @@
        },
        {
         "Name": "OTEL_PROPAGATORS",
-        "Value": "tracecontext,baggage,b3,xray"
+        "Value": "tracecontext,baggage,xray"
        },
        {
         "Name": "OTEL_DOTNET_DISTRO",

packages/@aws-cdk/aws-applicationsignals-alpha/test/integ.ecs-enablement-replica.js.snapshot/tree.json

@@ -50,7 +50,7 @@
        },
        {
         "Name": "OTEL_PROPAGATORS",
-        "Value": "tracecontext,baggage,b3,xray"
+        "Value": "tracecontext,baggage,xray"
        },
        {
         "Name": "JAVA_TOOL_OPTIONS",

packages/@aws-cdk/aws-applicationsignals-alpha/test/integ.ecs-enablement-sidecar.js.snapshot/ApplicationSignalsDotnetApp-Sidecar.template.json

@@ -50,7 +50,7 @@
        },
        {
         "Name": "OTEL_PROPAGATORS",
-        "Value": "tracecontext,baggage,b3,xray"
+        "Value": "tracecontext,baggage,xray"
        },
        {
         "Name": "NODE_OPTIONS",

packages/@aws-cdk/aws-applicationsignals-alpha/test/integ.ecs-enablement-sidecar.js.snapshot/ApplicationSignalsJavaApp-Sidecar.template.json

@@ -63,7 +63,7 @@
        },
        {
         "Name": "OTEL_PROPAGATORS",
-        "Value": "tracecontext,baggage,b3,xray"
+        "Value": "tracecontext,baggage,xray"
        },
        {
         "Name": "OTEL_PYTHON_DISTRO",