Cherry-pick #7754 into v1.68.x

[purnesh42H]

Original PR: #7754

RELEASE NOTES:

• credentials: TLS credentials created via NewTLS that use tls.Config.GetConfigForClient will now have necessary gRPC-Go defaults, namely CipherSuites, supported TLS versions and ALPN configured automatically. This handling was already present for configs not using the GetConfigForClient function.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 81.65%. Comparing base (056dc64) to head (bcfee8a).
Report is 1 commits behind head on v1.68.x.

Additional details and impacted files

@@             Coverage Diff             @@
##           v1.68.x    #7813      +/-   ##
===========================================
- Coverage    81.80%   81.65%   -0.16%     
===========================================
  Files          364      364              
  Lines        35899    35910      +11     
===========================================
- Hits         29367    29321      -46     
- Misses        5345     5384      +39     
- Partials      1187     1205      +18     

Files with missing lines	Coverage Δ
credentials/tls.go	86.57% <100.00%> (+1.06%)	⬆️

... and 21 files with indirect coverage changes