test(bridge/opentracing): bind gRPC server to loopback

[jstar0]

Summary

• Bind the OpenTracing bridge gRPC test server to an explicit IPv4 loopback address instead of an unspecified listener address.
• Surface listener creation failures through the test helper.

This is a test-only reliability change. It does not affect exported APIs or runtime behavior.

Testing

• Before this change, go test -timeout 60s ./... in bridge/opentracing consistently failed TestBridgeTracer_ExtractAndInject_gRPC with error reading server preface: EOF.
• go test -timeout 60s -run '^TestBridgeTracer_ExtractAndInject_gRPC$' -count=20
• go test -timeout 60s -race -run '^TestBridgeTracer_ExtractAndInject_gRPC$' -count=10
• go test -timeout 60s -race ./... in bridge/opentracing

All three post-change commands passed. make precommit completed generation, formatting, linting, README, and module checks, and passed the updated bridge test before stopping at an unrelated OTLP gRPC integration test with the same server-preface EOF in the local environment.

[jstar0]

This is a test-only reliability change with no runtime or API behavior change, so it does not need a release-note entry. The changelog workflow documents Skip Changelog for this case. I do not have permission to apply labels; could a maintainer add that label when convenient?

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 88.5%. Comparing base (9ba91a2) to head (6052bfc).

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #8904     +/-   ##
=======================================
- Coverage   88.5%   88.5%   -0.1%     
=======================================
  Files        333     333             
  Lines      21101   21101             
=======================================
- Hits       18687   18684      -3     
- Misses      2414    2417      +3     

see 2 files with indirect coverage changes

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[jstar0]

Synced this branch with current main in signed merge commit 6052bfc. The only conflict was CHANGELOG.md; the merge keeps the #8904 test-reliability entry alongside the current unreleased entries.

Verification before the update:

• go test ./... in bridge/opentracing
• ./verify_released_changelog.sh main
• repository make precommit

The current head is conflict-free and has restarted the hosted matrix; the changelog and released-changelog guards are already green.