feat(python): Allow Python Enums as dtype inputs

[stinodego]

Closes https://github.com/pola-rs/polars/issues/19724

Python Enums (and StrEnums) can now be used as dtype inputs, and can be passed to the Polars Enum constructor.

[codecov[bot]]

Codecov Report

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

Project coverage is 79.48%. Comparing base (7b07c85) to head (63b576f). Report is 4 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #19926 +/- ## ========================================== + Coverage 79.44% 79.48% +0.04% ========================================== Files 1554 1554 Lines 215618 216140 +522 Branches 2454 2456 +2 ========================================== + Hits 171289 171795 +506 - Misses 43770 43787 +17 + Partials 559 558 -1 ```

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[ritchie46]

Nice!