`pipx run`: reinstall the package if exceptions are raised

[dukecat0]

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

Summary of changes

pipx run will now reinstall the package if exceptions are raised when trying to run the app (such as missing Python interpreter symlink).

Closes #449

Test plan

Tested by running

pipx run pycowsay

Then remove the symlink to the Python interpreter in the temporary venv of pycowsay.

And run pipx run pycowsay again. It will now fix the venv instead of raising error.

[uranusjr]

Makes sense, but it could be a pain to debug such a failure. Maybe a flag to stop the auto-reinstall would be a good idea?

[gaborbernat]

Seems stalled, closing until more contribution when we can reopen.