using uv in test action

[williambdean]

Description

Following #1989, this uses uv for the environment in the action.

Related Issue

• Closes #
• Related to #

Checklist

• Checked that the pre-commit linting/style checks pass. Feel free to comment pre-commit.ci autofix to auto-fix.
• Included tests that prove the fix is effective or that the new feature works
• Added necessary documentation (docstrings and/or example notebooks) using numpydoc format.
• If you are a pro: each commit corresponds to a relevant logical change

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📚 Documentation preview 📚: https://pymc-marketing--1991.org.readthedocs.build/en/1991/

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 26.76%. Comparing base (9287c49) to head (1088b9b).
⚠️ Report is 1 commits behind head on main.

❗ There is a different number of reports uploaded between BASE (9287c49) and HEAD (1088b9b). Click for more details.

HEAD has 20 uploads less than BASE

Flag	BASE (9287c49)	HEAD (1088b9b)
	23	3

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #1991       +/-   ##
===========================================
- Coverage   93.54%   26.76%   -66.78%     
===========================================
  Files          67       67               
  Lines        8966     8966               
===========================================
- Hits         8387     2400     -5987     
- Misses        579     6566     +5987     

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