client: Add retry logic on Pubsub 429 error during connect (backport #19990)

[mergify]

This is an automatic backport of pull request #19990 done by Mergify.

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[mergify]

automerge label removed due to a CI failure

[joncinque]

The older version of tungstenite used by 1.7 doesn't give the full response on error, just the status code. To adapt to that limitation, this version will just check the status code and do a normal exponential backoff of .5s * 2 ^ retries

[codecov]

Codecov Report

Merging #20002 (d8fd760) into v1.7 (d0143da) will decrease coverage by 0.0%.
The diff coverage is 0.0%.

@@            Coverage Diff            @@
##             v1.7   #20002     +/-   ##
=========================================
- Coverage    82.2%    82.2%   -0.1%     
=========================================
  Files         439      439             
  Lines      124912   124924     +12     
=========================================
- Hits       102751   102739     -12     
- Misses      22161    22185     +24