Omit `.git` worktree indexing (#9281)

Closes https://github.com/zed-industries/zed/issues/9174

Release Notes:

- Fixed panics when `.git` was opened as a Zed worktree
([9174](https://github.com/zed-industries/zed/issues/9174))
109482761bKirill Bulatov committed on 3/13/2024, 2:35:44 PM· committed by GitHubparent572ba3f
2 files changedLine totals unavailable