fix(apigateway): correct invalid JSON in StepFunctions 500 response template

Author: aemada-aws

packages/aws-cdk-lib/aws-apigateway/lib/integrations/stepfunctions.ts

@@ -214,7 +214,9 @@ function integrationResponse() {
       selectionPattern: '5\\d{2}',
       statusCode: '500',
       responseTemplates: {
-        'application/json': '"error": $input.path(\'$.error\')',
+        'application/json': `{
+          "error": "$input.path('$.error')"
+        }`,
       },
     },
   ];

packages/aws-cdk-lib/aws-apigateway/test/integrations/stepfunctions.test.ts

@@ -558,7 +558,9 @@ function getIntegrationResponse() {
       SelectionPattern: '5\\d{2}',
       StatusCode: '500',
       ResponseTemplates: {
-        'application/json': '"error": $input.path(\'$.error\')',
+        'application/json': `{
+          "error": "$input.path('$.error')"
+        }`,
       },
     },
   ];