cherry-pick #7861 to 1.68.x

[dfawley]

We will need a patch release for this. Can you take care of that please @purnesh42H?

RELEASE NOTES:

• credentials/alts: disable SRV and TXT lookups for handshaker service to prevent timeouts when retrieving credentials on systems containing a known bug in systemd-resolved.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 81.58%. Comparing base (eff4b16) to head (a7fe533).
Report is 1 commits behind head on v1.68.x.

Additional details and impacted files

@@             Coverage Diff             @@
##           v1.68.x    #7873      +/-   ##
===========================================
- Coverage    81.76%   81.58%   -0.19%     
===========================================
  Files          364      364              
  Lines        35910    35914       +4     
===========================================
- Hits         29363    29300      -63     
- Misses        5354     5411      +57     
- Partials      1193     1203      +10     

Files with missing lines	Coverage Δ
...ntials/alts/internal/handshaker/service/service.go	69.23% <100.00%> (+2.56%)	⬆️
internal/resolver/dns/dns_resolver.go	89.47% <100.00%> (+0.07%)	⬆️

... and 19 files with indirect coverage changes