Update preview installation of Python executables to be non-fatal (#14612)
Previously, if installation of executables into the bin directory failed
we'd with a non-zero code. However, if we make this behavior the default
we don't want it to be fatal. There's a `--bin` opt-in to _require_
successful executable installation and a `--no-bin` opt-out to silence
the warning / opt-out of installation entirely.
Part of https://github.com/astral-sh/uv/issues/14296 — we need this
before we can stabilize the behavior.
In #14614 we do the same for writing entries to the Windows registry.