[WIP]Support custom bigquery schema for perf alert tool

[AnandInguva]

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[codecov]

Codecov Report

Merging #28722 (4bf8636) into master (b9ac87e) will increase coverage by 0.00%.
Report is 5 commits behind head on master.
The diff coverage is n/a.

❗ Current head 4bf8636 differs from pull request most recent head f11c046. Consider uploading reports for the commit f11c046 to get more accurate results

@@           Coverage Diff           @@
##           master   #28722   +/-   ##
=======================================
  Coverage   71.96%   71.96%           
=======================================
  Files         680      680           
  Lines      100172   100172           
=======================================
+ Hits        72085    72088    +3     
+ Misses      26511    26508    -3     
  Partials     1576     1576           

Flag	Coverage Δ
python	82.54% <ø> (+<0.01%)	⬆️

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see 4 files with indirect coverage changes

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