Remove installed version of pip from distribution

[jjhelmus]

Distribution artifacts include two separate pip distribution:

• The one included with ensurepip
• The one installed in site-packages.

The former is used when creating a virtual environment (e.g. python -m venv).

The later is used if python -m pip is run from the unpacked distribution which IMHO should not be done, at minimum a virtual environment should be created.

When installed by uv I do not think the installed version of pip is ever used.

[indygreg]

PBS is used beyond uv. And pip has been available in site-packages long before Astral existed.

This is proposing a backwards incompatible change and it may break customers.

[jjhelmus]

Thanks for the context and background @indygreg.

I originally had "Consider removing" in the title, as I was looking for feedback on this change. Feedback recieved. 😄

Also I have used the installed pip in PBS in various cases. Being able to tar xf <pbs>; ./python/install/bin/python -m pip ... is useful.