Avoid stripping root for user path display (#6865)
## Summary
Closes https://github.com/astral-sh/uv/issues/6840.
## Test Plan
```
❯ ~/workspace/uv/target/debug/uv pip list --verbose
DEBUG uv 0.4.0
DEBUG Searching for Python interpreter in system path
DEBUG Found `cpython-3.12.3-macos-aarch64-none` at `/Users/crmarsh/.local/share/rtx/installs/python/3.12.3/bin/python3` (search path)
DEBUG Using Python 3.12.3 environment at /Users/crmarsh/.local/share/rtx/installs/python/3.12.3/bin/python3
```
