ref: migrate to uv

[aldy505]

Why I want to migrate to uv:

• More modern tooling
• Making it easy for new contributors who don't really understand Python well enough (like me) to easily setup their Python virtual environment and everything
• Although you can't run (or actually, you shouldn't) run the integration test on your local machine, one benefit is you get the typings when developing the tests locally.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.49%. Comparing base (ebace8c) to head (4754cd0).
⚠️ Report is 1 commits behind head on master.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #4061   +/-   ##
=======================================
  Coverage   99.49%   99.49%           
=======================================
  Files           3        3           
  Lines         197      197           
=======================================
  Hits          196      196           
  Misses          1        1           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[joshuarli]

you can remove setup-python; setup-venv does this for you and infers the version from .python-version

[joshuarli]

fix https://github.com/getsentry/self-hosted/pull/4061/files#r2594164958 and ship