client transport: Handle 1xx HTTP status HEADERS frames correctly

[vinothkumarr227]

Fixes: #8485

RELEASE NOTES: N/A

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 81.78%. Comparing base (9ac0ec8) to head (99675c3).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #8518      +/-   ##
==========================================
- Coverage   81.82%   81.78%   -0.04%     
==========================================
  Files         413      413              
  Lines       40518    40524       +6     
==========================================
- Hits        33153    33143      -10     
- Misses       5989     5998       +9     
- Partials     1376     1383       +7     

Files with missing lines	Coverage Δ
internal/transport/http2_client.go	92.15% <100.00%> (+0.33%)	⬆️

... and 20 files with indirect coverage changes

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