Rerun flaky tests in CI

[Wauplin]

Tests in CI are quite flaky lately. We have a retry_on_transient_errors wrapper to retry on OSError (git clone failed), TimeoutError or HTTP 502/504. But this wrapper just doesn't work (sorry I introduced it 2mo ago in #1725 🙄). This PR fixes this by using pytest-rerunfailures which seems to be far more robust and tested that doing it manually^^.

Note that only tests run in CI are rerun on failure. I did not make it a default locally as it's not compatible with --pdb. (+flaky tests are never failing locally in my experience).

[HuggingFaceDocBuilderDev]

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[Wauplin]

Yay! 🎉 🎉 🎉 Should have done it earlier 😄

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (7319ea4) 82.22% compared to head (faec54b) 82.31%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1914      +/-   ##
==========================================
+ Coverage   82.22%   82.31%   +0.08%     
==========================================
  Files          65       65              
  Lines        8092     8092              
==========================================
+ Hits         6654     6661       +7     
+ Misses       1438     1431       -7     

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[Wauplin]

I'm merging this without review as it's mainly to fix internal testing. Happy to make a follow-up PR in case you have some feedback @LysandreJik. (I'm merging to be able to have stable CI on other opened PRs).