gpui: Fix `RefCell already borrowed` in `WindowsPlatform::run` (#42506)

Relands #42440 

Fixes ZED-1VX

Release Notes:

- N/A *or* Added/Fixed/Improved ...
f2cadad49aLukas Wirth committed on 11/12/2025, 8:19:32 AM· committed by GitHubparent231d1b1
3 files changedLine totals unavailable