Check whether pip module exists in shared lib before performing any actions

[dukecat0]

• I have added an entry to docs/changelog.md

Summary of changes

Check whether pip module exists in shared lib before performing any actions.
Closes #1110

Test plan

Tested by running

nox -s test-3.11

[asyncon]

Will this actually solve the issue of post fedora upgrade with a new minor version 3.X of python?

If the file ~/.local/pipx/shared/bin/python3 points to a now updated version of python, it stands to reason that some of ~/.local/pipx/venvs/*/bin/python3 might also do the same. Which would then result in the same outcome of a python version mismatch and not finding the pip module in ~/.local/pipx/shared/lib/python3.X/site-packages because it's in python3.$((X-1)).

An alternate idea is to move the new the new pip module detection logic into the pipx.shared_libs._SharedLibs.is_valid property.

This solution would also work for all other commands as well such as install and upgrade.

[gaborbernat]

An alternate idea is to move the new the new pip module detection logic into the pipx.shared_libs._SharedLibs.is_valid property.

This solution would also work for all other commands as well such as install and upgrade.

[gaborbernat]

Merge conflicts.

[gaborbernat]

[gaborbernat]

Ah, new merge conflicts.

[dukecat0]

Fixed

[gaborbernat]