Copy entrypoints that have a shebang that differs in `python` vs `python3` (#14970)
In https://github.com/astral-sh/uv/issues/14919 it was reported that
uv's behavior differed after the first invocation. I noticed we weren't
copying entrypoints after the first invocation. It turns out the
shebangs were written with `.../python` but on a subsequent invocation
the `sys.executable` was `.../python3` so we didn't detect these as
matching.
This is a pretty naive fix, but it seems much easier than ensuring the
entry point path exactly matches the subsequent `sys.executable` we
find.
I guess we should fix this in reverse too? but I think we might always
prefer `python3` when loading interpreters from environments.
See #14790 for more background.