Simplify dimension addition - remove ordering logic

Use push() instead of unshift/splice to add Service and Environment
dimensions without enforcing specific position in the dimensions array.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: syed-ahsan-ishtiaque

aws-distro-opentelemetry-node-autoinstrumentation/src/exporter/aws/metrics/emf-exporter-base.ts

@@ -269,7 +269,7 @@ export abstract class EMFExporterBase implements PushMetricExporter {
           serviceName = String(serviceAttr);
         }
       }
-      dimensionNames.unshift(SERVICE_DIMENSION);
+      dimensionNames.push(SERVICE_DIMENSION);
       emfLog[SERVICE_DIMENSION] = serviceName;
     }
 
@@ -298,9 +298,7 @@ export abstract class EMFExporterBase implements PushMetricExporter {
         environment = this.getDefaultEnvironmentForPlatform(resource);
       }
 
-      // Insert after Service if present, otherwise at beginning
-      const insertIndex = dimensionNames.includes(SERVICE_DIMENSION) ? 1 : 0;
-      dimensionNames.splice(insertIndex, 0, ENVIRONMENT_DIMENSION);
+      dimensionNames.push(ENVIRONMENT_DIMENSION);
       emfLog[ENVIRONMENT_DIMENSION] = environment;
     }
   }

aws-distro-opentelemetry-node-autoinstrumentation/test/exporter/aws/metrics/aws-cloudwatch-emf-exporter.test.ts

@@ -1013,8 +1013,8 @@ describe('TestAWSCloudWatchEMFExporter', () => {
       expect(result).toHaveProperty('Environment', 'new-env');
     });
 
-    it('TestDimensionOrderServiceThenEnvironment', () => {
-      /* Test that Service comes before Environment in dimensions array. */
+    it('TestDimensionsAddedAlongsideExisting', () => {
+      /* Test that Service and Environment are added alongside existing dimensions. */
       process.env['OTEL_METRICS_ADD_APPLICATION_SIGNALS_DIMENSIONS'] = 'true';
 
       const gaugeRecord: MetricRecord = {
@@ -1026,10 +1026,10 @@ describe('TestAWSCloudWatchEMFExporter', () => {
       const result = exporter['createEmfLog']([gaugeRecord], resource, 1234567890);
 
       const cwMetrics = result._aws.CloudWatchMetrics[0];
-      // Dimensions should be: ['Service', 'Environment', 'existing_dim']
-      expect(cwMetrics.Dimensions![0][0]).toEqual('Service');
-      expect(cwMetrics.Dimensions![0][1]).toEqual('Environment');
-      expect(cwMetrics.Dimensions![0][2]).toEqual('existing_dim');
+      // All three dimensions should be present
+      expect(cwMetrics.Dimensions![0]).toContain('Service');
+      expect(cwMetrics.Dimensions![0]).toContain('Environment');
+      expect(cwMetrics.Dimensions![0]).toContain('existing_dim');
     });
 
     it('TestEnvVarCaseInsensitive', () => {