Closes #47098 

The root cause of this issue is related to how `Poetry` (and the
upstream `pet-poetry` library) handles path hashing. While perhaps it's
an upstream behavior, we can easily fix it on the Zed side.

The related code are

https://github.com/zed-industries/zed/blob/7ce845210d3af82a57a7518e0abe8c167d60cc6a/crates/languages/src/python.rs#L1181-L1211

In my debugging, I found that `worktree_root` takes the form
`/home/user/project`, but `config.workspace_directories` often ends up
as `/home/user/project/`(with a trailing slash). Normally this wouldn't
be an issue, but `Poetry` generates environment names based on the hash
of the absolute path. Since the hashes for `/home/user/project` and
`/home/user/project/` are different, `pet-poetry` fails to find the
environment.

The fix is straightforward: we just need to ensure the trailing `/` is
removed so the hashes match.

Release Notes:

- Fixed poetry environment not discovered on linux