Conformity of client interceptor(s) with the official grpc.*ClientInterceptor-interfaces

[juandelacruz-calvo]

Summary

This PR is a rebased version of PR #3384 that aims to update the OpenTelemetryClientInterceptor to support official gRPC client interceptor interfaces introduced in gRPC v1.8.0.

Changes

• Remove external implementation of gRPC client interceptors (package grpcext)
• Adapt the _client.py module based on the _aio_client.py module design
• Remove the RpcInfo class from utilities.py
• Update test_client_interceptor_trace_context_propagation tests
• Update semantic conventions to use the new incubating attributes

Test plan

Tested locally, working with grpc client instrumentation, also working with PubSub consuming and publishing

Related Issues

• Original PR: Conformity of client intereptor(s) with the official grpc.*ClientInterceptor-interfaces #3384
• Rebased on latest main to resolve conflicts

🤖 Generated with Claude Code

[juandelacruz-calvo]

This is really no longer needed to fix the issue for PubSub on GCP, since they released specific properties to instrument their software with OpenTelemetry: https://cloud.google.com/pubsub/docs/open-telemetry-tracing

But it helps to add manual intercepts to gRPC clients