chore(orchestrator): unify OTEL env variable name in benchmarks (#2351)

The concurrent benchmark was based on the original benchmark test, which
used OTEL_EXPORTER_OTLP_ENDPOINT. The rest of the codebase consistently
uses OTEL_COLLECTOR_GRPC_ENDPOINT. Unify the benchmarks to match.

Author: arkamar

packages/orchestrator/benchmarks/benchmark_test.go

@@ -80,7 +80,7 @@ func BenchmarkBaseImageLaunch(b *testing.B) {
 		return utils.Must(filepath.Abs(s))
 	}
 
-	endpoint := os.Getenv("OTEL_EXPORTER_OTLP_ENDPOINT")
+	endpoint := os.Getenv("OTEL_COLLECTOR_GRPC_ENDPOINT")
 	if endpoint != "" {
 		spanExporter, err := telemetry.NewSpanExporter(b.Context(),
 			otlptracegrpc.WithEndpoint(endpoint),

packages/orchestrator/benchmarks/concurrent_benchmark_test.go

@@ -166,7 +166,7 @@ func BenchmarkConcurrentResume(b *testing.B) {
 	}
 
 	// optional OTEL tracing
-	endpoint := os.Getenv("OTEL_EXPORTER_OTLP_ENDPOINT")
+	endpoint := os.Getenv("OTEL_COLLECTOR_GRPC_ENDPOINT")
 	if endpoint != "" {
 		spanExporter, err := telemetry.NewSpanExporter(b.Context(),
 			otlptracegrpc.WithEndpoint(endpoint),