[TEST] Functional tests for OTLP GRPC MTLS export #2208
Description
This is a follow up on:
Add functional tests for validating OTLP gRPC with client certificate chain + Server ca certificate.
Ref- https://github.com/open-telemetry/opentelemetry-cpp/tree/main/functional/otlp