revert changes in the .env.example

Author: Lingling Peng

.env.example

@@ -1,6 +1,5 @@
 ## Here are the environment variables you can set for the Synapse Python client to configure OpenTelemetry tracing and metrics:
 # You can copy this file to `.env` and fill in the values as needed.
-# OTEL_SERVICE_NAME=my-service-using-synapse-python-client
-# OTEL_EXPORTER_OTLP_ENDPOINT=https://ingest.us.signoz.cloud
-# OTEL_SERVICE_INSTANCE_ID=local
-# OTEL_EXPORTER_OTLP_HEADERS=signoz-ingestion-key=<your key>
+# OTEL_EXPORTER_OTLP_ENDPOINT=http://fill-me-in
+# OTEL_SERVICE_INSTANCE_ID=local_development_testing
+# OTEL_EXPORTER_OTLP_HEADERS=# Authorization