interop/xds: Increase go log verbosity to 99 so that EDS is logged (v1.60.x backport)

[XuanWang-Amos]

Backport of #6860 to v1.60.x.

gRPC-go versions v1.54.x and later don't log ADS responses anymore. This makes it hard to debug without being able to see EDS resources. Logging behavior was changed by #5992.

This PR updates XdsTestServer/XdsTestClient Docker images so that GRPC_GO_LOG_VERBOSITY_LEVEL is increased from 2 to 99.

RELEASE NOTES: N/A

[codecov]

Codecov Report

Merging #6882 (2878fb3) into v1.60.x (0483dc9) will decrease coverage by 0.01%.
The diff coverage is n/a.

❗ Current head 2878fb3 differs from pull request most recent head ff76a48. Consider uploading reports for the commit ff76a48 to get more accurate results

Additional details and impacted files

@@             Coverage Diff             @@
##           v1.60.x    #6882      +/-   ##
===========================================
- Coverage    83.70%   83.69%   -0.01%     
===========================================
  Files          286      286              
  Lines        30797    30797              
===========================================
- Hits         25778    25776       -2     
- Misses        3960     3965       +5     
+ Partials      1059     1056       -3     

see 19 files with indirect coverage changes