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 27.04%. Comparing base (47d500c) to head (8968dba).

❗ There is a different number of reports uploaded between BASE (47d500c) and HEAD (8968dba). Click for more details.

HEAD has 20 uploads less than BASE

Flag	BASE (47d500c)	HEAD (8968dba)
	23	3

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #1991       +/-   ##
===========================================
- Coverage   93.89%   27.04%   -66.85%     
===========================================
  Files          67       67               
  Lines        9221     9221               
===========================================
- Hits         8658     2494     -6164     
- Misses        563     6727     +6164     

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