feat: Targets now emit record count from the built-in batch file processor

[edgarrmondragon]

Closes #2702

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📚 Documentation preview 📚: https://meltano-sdk--2703.org.readthedocs.build/en/2703/

[codspeed-hq]

CodSpeed Performance Report

Merging #2703 will not alter performance

_{Comparing edgarrmondragon/feat/records-batch-metric (8d8e032) with main (9bf104e)}

Summary

✅ 6 untouched benchmarks

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 90.51%. Comparing base (9bf104e) to head (8d8e032).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2703   +/-   ##
=======================================
  Coverage   90.50%   90.51%           
=======================================
  Files          62       62           
  Lines        4994     4996    +2     
  Branches      974      974           
=======================================
+ Hits         4520     4522    +2     
  Misses        328      328           
  Partials      146      146           

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