This PR fixes the default behaviour of setting `app_id` to `None` which
breaks the rules based management by KWin as the first commit doesn't
have the actual `app_id` and apply initially setting stops checking for
the window by when it updates.

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)
- [x] Tests cover the new/changed behavior
- [x] Performance impact has been considered and is acceptable

Closes #53962

Release Notes:

- Fixed KWin not respecting Zed's rules due to mismatch of toplevel
app_id at startup