[Feature Request] Upgrades to GIF Picker

The following is a list of problems and proposed suggestions for issues faced with the current implementation of the GIF Picker on both Desktop and Mobile.

• Sometimes, GIFs that are stored in Favorite GIFs are removed by the site they're hosted on, including the Discord CDN. In the event that the GIF Picker can't load a preview due to the aforementioned favorite GIF being unavailable, an error placeholder should appear in its place instead of the blurple (on Web/Desktop) or gray (on Mobile) rectangle. This will make it easier to manage Favorite GIFs by removing non-working ones.
• On Web and Desktop, the GIF Picker closes once a GIF is selected. I assume this is to help prevent spam of GIFs, but with the current system of Favorite GIF management, this makes it very frustrating to clear out unavailable GIFs as mentioned above. Keeping the GIF Picker open by holding a key, like with holding Shift in the Emoji Picker, should be available as an interim option.
• On Mobile, tapping on a non-loading or unloadable GIF doesn't provide any feedback. A pop-up or modal that says that the GIF is unavailable would help users to identify why nothing is happening.
• There is currently no way to add or remove Favorite GIFs on Mobile. Adding an option in the pop-up menu upon tapping and holding the desired GIF in a message or in the GIF Picker would be an elegant solution.