Replace get_theme_file_path() with self:get_file_path_from_theme().

[desrosj]

Description

This copies the fix in Core-52077 from WordPress trunk to the plugin.

After Core-52049, style assets in the admin were not loading due to a fatal error when SCRIPT_DEBUG was set to false.

Checklist:

• My code is tested.
• My code follows the WordPress code style.
• My code follows the accessibility standards.
• I've tested my changes with keyboard and screen readers.
• My code has proper inline documentation.
• I've included developer documentation if appropriate.
• I've updated all React Native files affected by any refactorings/renamings in this PR (please manually search all *.native.js files for terms that need renaming or removal).

[Mamaduka]

Hi, @desrosj

Sorry, I just saw the recent comments on the track ticket. This change will break child themes.

The method should return true if the parent or child has a theme.json file. It is required to load "Global Styles" correctly.

It think we should duplicate get_theme_file_path logic in :: theme_has_support.

[desrosj]

Closing in favor of #36398.