Cut `fs` dependency from `theme` (#52482)

Trying to clean up the deps here for potential use of the ui crate in
web

Release Notes:

- N/A or Added/Fixed/Improved ...
354bc35974Lukas Wirth committed on 3/27/2026, 8:17:30 AM· committed by GitHubparent80b86ce
14 files changedLine totals unavailable