Untyped parameters with None default no longer skipped when fail_untyped=True

[mauvilsa]

What does this PR do?

Fixes #696

Before submitting

• Did you read the contributing guideline?
• [n/a] Did you update the documentation? (readme and public docstrings)
• Did you write unit tests such that there is 100% coverage on related code? (required for bug fixes and new features)
• Did you verify that new and existing tests pass locally?
• Did you make sure that all changes preserve backward compatibility?
• Did you update the CHANGELOG? (not for typos, docs, test updates, or minor internal changes/refactors)

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 100.00%. Comparing base (2fc33fd) to head (f709d4d).
Report is 1 commits behind head on main.

✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff            @@
##              main      #697   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           22        22           
  Lines         6755      6755           
=========================================
  Hits          6755      6755           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.