Improvements to gated global styles experience

[annezazu]

What follows are some tasks to improve the experience of upgrading between global styles on a free plan (or personal for now until gating is removed from there again). I created this from current known issues. cc @jordesign @inaikem for any additional items you can add from users or your own walkthroughs here.

Tasks

• Gated styles: Ensure all prompts to remove premium styles automatically works #97730
• Unable to change from a premium style back to default during signup #95578
• Limited Global Styles notices are visible in the distraction free mode #81636
• Design only task for now: Gated styles: Redesign front end prompt to upgrade to paid styles #98039