update warning filters in tests for pytest 8

[braingram]

pytest 8 includes a change to how "pytest.warns" behaves (it now re-emits non-matched warnings). Running the stdatamodels test suite against pytest 8 (rc1) there is one failing test test_ndarray_validation due to this change.

This PR updates the warning filters in test_ndarray_validation to work with pytest 8.

Checklist

• [ ] added entry in CHANGES.rst (either in Bug Fixes or Changes to API)
• [ ] updated relevant tests
• [ ] updated relevant documentation
• [ ] updated relevant milestone(s)
• [ ] added relevant label(s)

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (ee53eab) 0.00% compared to head (0a21094) 64.84%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #245 +/- ## =========================================== + Coverage 0 64.84% +64.84% =========================================== Files 0 103 +103 Lines 0 5694 +5694 =========================================== + Hits 0 3692 +3692 - Misses 0 2002 +2002 ```

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