`git clean` in a python project triggers invalid python notification

In this scenario there is an existing valid environment (created with a .gitignore in it). and performing `git clean` removes that environment. This causes python extension to detect that the environment has changed. Python extension then tries to look up info to get data on the environment. But there is no environment and that leads to invalid environment notification.

The payload names no files, tests, or entry points. Reproduce the sequence with a valid Python environment, a .gitignore, and git clean; trace the environment-change handling and verify that removing the environment no longer produces an invalid-environment notification.

Written by the indexing model from the issue text.