[processorhelper] update units for metrics

[codeboten]

This updates units for processhelper's internal telemetry.

Related #10556

Fixes #10651

For this PR i updated metadata.yaml and ran make gogenerate, then make -C processor test

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 92.33%. Comparing base (43ed618) to head (5e1c134).
Report is 6 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #10647      +/-   ##
==========================================
+ Coverage   92.32%   92.33%   +0.01%     
==========================================
  Files         397      403       +6     
  Lines       18701    18733      +32     
==========================================
+ Hits        17265    17297      +32     
  Misses       1076     1076              
  Partials      360      360              

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[crobert-1]

Out of ignorance, what kind of change do we consider changing metric units? Do we need a changelog entry for this?

[codeboten]

Out of ignorance, what kind of change do we consider changing metric units? Do we need a changelog entry for this?

I believe we should have a changelog for this, will add one shortly

[codeboten]

Changelog added, PTAL @crobert-1