## Summary
<!-- What's the purpose of the change? What does it do, and why? -->
Changes in this PR https://github.com/astral-sh/ruff/pull/13591 did not
allow correct discovery in pip build environments.
```python
# both of these variables are tuple[str, str] (length is 2)
first, second = os.path.split(paths[0]), os.path.split(paths[1])
# so these length checks are guaranteed to fail even for build environment folders
if (
len(first) >= 3
and len(second) >= 3
...
)
```
~~Here we instead use `pathlib`, and we check all `pip-build-env-` paths
for the folder that is expected to contain the `ruff` executable.~~
Here we update the logic to more properly split out the path components
that we use for `pip-build-env-` inspection.
## Test Plan
I've checked this manually against a workflow that was failing, I'm not
sure what to do for real tests. The same issues apply as with the
previous PR.
---------
Co-authored-by: Jonathan Surany <jsurany@bloomberg.net>
Co-authored-by: Charlie Marsh <charlie.r.marsh@gmail.com>