gpui: Ensure tab index handles are properly reused across frames (#35235)

This fixes an issue where focus handles with a tab index would get lost
between rendered frames because the focus handles were not reused for
the following paint cycle.

Release Notes:

- N/A
158f65fd1eFinn Evers committed on 7/28/2025, 9:33:20 PM· committed by GitHubparentfa6b1a0
3 files changedLine totals unavailable