v1.16: ci: add the ability to use GCS backend for sccache (backport of #33967)

[mergify]

This is an automatic backport of pull request #33967 done by Mergify.

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[codecov]

Codecov Report

Merging #33983 (2912b1c) into v1.16 (2912b1c) will not change coverage.
Report is 1 commits behind head on v1.16.
The diff coverage is n/a.

❗ Current head 2912b1c differs from pull request most recent head 74ff0d2. Consider uploading reports for the commit 74ff0d2 to get more accurate results

@@           Coverage Diff           @@
##            v1.16   #33983   +/-   ##
=======================================
  Coverage    81.8%    81.8%           
=======================================
  Files         766      766           
  Lines      209076   209076           
=======================================
  Hits       171125   171125           
  Misses      37951    37951