Draft: gtkconfig: Fix dark theme preference going out-of-sync
The General/ColorScheme change arrives earlier than Colors:Window probably due to the order the changes are applied. Thus, the previous theme preference ends up getting set when a change was applied.
Quickly fixing this by calling setDarkThemePreference once Colors:Window actually gets changed. In the future we might want to:
- Have automatic dependency tracking to avoid the same kind of errors.
- Make changes apply atomically (in batch) to avoid any temporary inconsistencies.