OTEL_SERVICE_NAME env variable is not applied to the telemetry

[RohitRanjanMS]

When setting the OTEL_SERVICE_NAME environment variable, the expected service name does not appear in the exported telemetry. Instead, the default or fallback name is used. This makes it difficult to correctly identify services in observability platforms.

Steps to Reproduce:

• Set OTEL_SERVICE_NAME=MyService in the environment.
• Run the application with OpenTelemetry enabled.
• Inspect the telemetry data (e.g., traces, metrics).
• Observe that the service name is not MyService.