Follow-up to https://github.com/astral-sh/ruff/pull/17991 ensuring we do not allow detection of system environments when the origin is `VIRTUAL_ENV` or a discovered `.venv` directory — i.e., those always require a `pyvenv.cfg` file.
Follow-up to https://github.com/astral-sh/ruff/pull/17991 ensuring we do not allow detection of system environments when the origin is `VIRTUAL_ENV` or a discovered `.venv` directory — i.e., those always require a `pyvenv.cfg` file.