The blame popover shouldn't appear when the cursor hovers over the
annotation but on a different pane.

Before:


https://github.com/user-attachments/assets/dbf6f7b5-e27f-495b-8d6f-fa75a4feee18

After:


https://github.com/user-attachments/assets/d5e186df-4ebf-4b4c-bb5f-4d9e7b0f62c7

Self-Review Checklist:

- [x] I've reviewed my own diff for quality, security, and reliability
- [x] Unsafe blocks (if any) have justifying comments
- [x] The content is consistent with the [UI/UX
checklist](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist)
- [ ] Tests cover the new/changed behavior
- [x] Performance impact has been considered and is acceptable

Release Notes:

- Fixed a bug that caused git blame annotations to be hoverable from a
different pane.