try to leverage existed env variable instead of introducing new one

Signed-off-by: Tsai, Louie <[email protected]>

comps/__init__.py

@@ -51,7 +51,7 @@
 from comps.cores.mega.micro_service import MicroService, register_microservice, opea_microservices
 
 # Telemetry
-if os.getenv("ENABLE_OPEA_TELEMETRY", "false").lower() == "true":
+if os.getenv("TELEMETRY_ENDPOINT") is not None:
     from comps.cores.telemetry.opea_telemetry import opea_telemetry
 
 # Common