Revised the App Design Guidelines (Summer 2024)

We've introduced the following changes to improve and update the App Design Guidelines:

• FullscreenBar usage within a max modal is now a "Do Not". The FullscreenBar section of the App Design Guidelines has been removed as it is no longer supported.
• Proper grammar is now included as a "Must Do".
• Using the App Bridge Contextual Save Bar API (where applicable) is now a "Must Do".
• Added a new section to the App Design Guidelines that includes specific requirements for subscription apps.