Validate that discovered interpreters meet the Python preference (#7934)
Closes https://github.com/astral-sh/uv/issues/5144
e.g.
```
❯ cargo run -q -- sync --python-preference only-system
Using CPython 3.12.6 interpreter at: /opt/homebrew/opt/python@3.12/bin/python3.12
Removed virtual environment at: .venv
Creating virtual environment at: .venv
Resolved 9 packages in 14ms
Installed 8 packages in 9ms
+ anyio==4.6.0
+ certifi==2024.8.30
+ h11==0.14.0
+ httpcore==1.0.5
+ httpx==0.27.2
+ idna==3.10
+ ruff==0.6.7
+ sniffio==1.3.1
❯ cargo run -q -- sync --python-preference only-managed
Using CPython 3.12.1
Removed virtual environment at: .venv
Creating virtual environment at: .venv
Resolved 9 packages in 14ms
Installed 8 packages in 11ms
+ anyio==4.6.0
+ certifi==2024.8.30
+ h11==0.14.0
+ httpcore==1.0.5
+ httpx==0.27.2
+ idna==3.10
+ ruff==0.6.7
+ sniffio==1.3.1
```