Revert "Allow `--with-requirements` to load extensionless inline-metadata scripts" (#16861)
Reverts https://github.com/astral-sh/uv/pull/16805 /
https://github.com/astral-sh/uv/pull/16744
This also invalidates
- https://github.com/astral-sh/uv/pull/16855
- #16857
There's probably a way we can make this work, but detecting whether a
file is safe to read repeatedly is non-trivial, `is_file` returns `true`
for `/dev/stdin` on macOS so the approach from #16857 is not sufficient.
I spent a while trying to add `is_char_device` detection for macOS but
unfortunately that didn't work.