[release/8.0.3xx] Stop building source-build in non-1xx branches (#20634)

Co-authored-by: Nikola Milosavljevic <nikolam@microsoft.com>

Author: github-actions[bot]

.vsts-ci.yml

@@ -323,11 +323,6 @@ extends:
             buildArchitecture: arm64
             runTests: false
 
-      # Source Build
-      - template: /eng/common/templates-official/jobs/source-build.yml@self
-        parameters:
-          enableInternalSources: true
-
     - ${{ if and(ne(variables['System.TeamProject'], 'public'), notin(variables['Build.Reason'], 'PullRequest')) }}:
       - stage: Publish
         dependsOn:

.vsts-pr.yml

@@ -342,10 +342,6 @@ stages:
         linuxPortable: true
         runTests: false
 
-  - template: /eng/common/templates/jobs/source-build.yml
-    parameters:
-      enableInternalSources: true
-
 - ${{ if and(ne(variables['System.TeamProject'], 'public'), notin(variables['Build.Reason'], 'PullRequest')) }}:
   - stage: Publish
     dependsOn: