Remove auto watch feature flag (#59619)

## 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 adheres to Zed's UI standards
([UX/UI](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist)
and
[icon](https://github.com/zed-industries/zed/blob/main/crates/icons/README.md)
guidelines)
- [X] Tests cover the new/changed behavior
- [X] Performance impact has been considered and is acceptable

Release Notes:

- Added an auto-watch button to the collab panel that automatically
opens other participants' screen shares while you're in a call.
184cf97ee9Joseph T. Lyons committed on 6/26/2026, 9:13:01 PM· committed by GitHubparentaf3f790
4 files changedLine totals unavailable