infra: tox -e coverage-check

[speller26]

Added a coverage-check testenv to tox.ini, so tox will now fail if coverage falls below 100%

Issue #, if available:

Description of changes:

Testing done:

Merge Checklist

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (b5413c6) to head (4553caa).

Additional details and impacted files

@@            Coverage Diff            @@
##              main      #407   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           49        49           
  Lines         4964      4964           
  Branches       580       580           
=========================================
  Hits          4964      4964           

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