v1.68: remove opentelemetry module and pull into main module

[dfawley]

RELEASE NOTES (will need to be manual):

Dependencies

• Remove the experimental stats/opentelemetry module and instead add the experimental packages it contains directly into the main google.golang.org/grpc module.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 82.00%. Comparing base (7d2cf55) to head (d132952).
Report is 1 commits behind head on v1.68.x.

Additional details and impacted files

@@             Coverage Diff             @@
##           v1.68.x    #7936      +/-   ##
===========================================
+ Coverage    81.60%   82.00%   +0.39%     
===========================================
  Files          364      370       +6     
  Lines        35914    37251    +1337     
===========================================
+ Hits         29306    30546    +1240     
- Misses        5400     5467      +67     
- Partials      1208     1238      +30     

see 24 files with indirect coverage changes

[dfawley]

FYI this should address our side of googleapis/google-cloud-go#11283

[purnesh42H]

@dfawley how will this help the storage library who uses older version of grpc who are still looking for separate opentelemetry module in stats? I am assuming they have to update to the patch release?

[dfawley]

I am assuming they have to update to the patch release?

Correct. If they update to a version with this change then their users won't run into conflicts with our latest release.