build/pkgs/pytest*: Change to standard wheel packages

[mkoeppe]

Vote: https://groups.google.com/g/sage-devel/c/MIU-xo9b7pc
Vote (redo): https://groups.google.com/g/sage-devel/c/lPLoA7zaoyg

Fixes #31110

📝 Checklist

• The title is concise, informative, and self-explanatory.
• The description explains in detail what this PR is about.
• I have linked a relevant issue or discussion.
• I have created tests covering the changes.
• I have updated the documentation accordingly.

⌛ Dependencies

[mkoeppe]

@dimpase May I suggest that you take the time to try out this PR? If you want to understand how a "wheel" package (https://deploy-livedoc--sagemath.netlify.app/html/en/developer/packaging#package-source-types) is installed, maybe install using ./sage -i -s pytest and look at what's happening in venv/var/tmp/sage

[dimpase]

As I said, I object to endless proliferation of more and more python (wheel - in case of pure python - or source, doesn't really matter) packages in Sage. If these were pip packages it would be possible to avoid bringing 2 more dependencies into Sage

[mkoeppe]

As I said, I object

We already know that.

My suggestion above is friendly guidance to a level on which a discussion makes more sense than what's currently happening in https://groups.google.com/g/sage-devel/c/5kmxaw105lg

[github-actions]

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