Fix error message of ReactiveESMMetaClass

[MarcSkovMadsen]

Closing #1063

[Copilot]

Pull Request Overview

This PR ensures that error messages for parameters owned by classes using custom metaclasses derived from ParameterizedMetaclass correctly display the class name rather than the metaclass name.

• Updated _validate_error_prefix to recognize subclasses of ParameterizedMetaclass.
• Added a new test to verify that custom metaclass names no longer appear in error messages.

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
tests/teststringparam.py	Added test_reject_none_custom_metaclass to confirm the fix.
param/_utils.py	Changed prefix logic to use issubclass for detecting metaclass subclasses.

[maximlt]

@MarcSkovMadsen pre-commit is not happy.

[jbednar]

This change makes sense. Thanks for figuring this out and submitting the PR!

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 87.48%. Comparing base (b1c46e2) to head (63dbbe7).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1064   +/-   ##
=======================================
  Coverage   87.48%   87.48%           
=======================================
  Files           9        9           
  Lines        4961     4961           
=======================================
  Hits         4340     4340           
  Misses        621      621           

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