Add type hint to CounterCell

[jrmccluskey]

Experiment with adding an explicit int type hint to CounterCell's update method. This should avoid an accidental aggregation of non-ints that is only caught when trying to serialize the metric.

Should prevent #27469 in the future

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[codecov]

Codecov Report

Merging #27522 (087222f) into master (41e6628) will decrease coverage by 0.21%.
Report is 421 commits behind head on master.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master   #27522      +/-   ##
==========================================
- Coverage   71.16%   70.96%   -0.21%     
==========================================
  Files         861      865       +4     
  Lines      104547   105453     +906     
==========================================
+ Hits        74401    74834     +433     
- Misses      28597    29070     +473     
  Partials     1549     1549              

Flag	Coverage Δ
python	79.94% <ø> (-0.43%)	⬇️

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Files Changed	Coverage Δ
sdks/python/apache_beam/metrics/cells.py	82.11% <ø> (ø)

... and 48 files with indirect coverage changes

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[jrmccluskey]

PyDoc failure is as a result of #28104

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[jrmccluskey]

Run PythonDocs PreCommit

[tvalentyn]

The assessment in #27469 is that the issue is in TFX code - is that incorrect?

[jrmccluskey]

It is, this just also adds a type hint to the metric counter that should give a more clear type check error rather than the error only coming when the metric is serialized.

[tvalentyn]

gotcha, nice, thanks!

[jrmccluskey]

retest this please