[Media Display] Replace gifs with new gif viewer

[mplorentz]

We are improving the way gifs are displayed, alone or in a media gallery, according to these Figma designs. We have separated aspect ratio changes into #1171. For now all gifs will be displayed 4:3 aspect fill.

Gifs displayed should fulfill the following stories (detail):

• Gif Viewing in Nos

[joshuatbrown]

@setch-l Suggested testing steps:

1. Navigate to Settings
2. Toggle Enable new media display to "On"
3. Find or post a GIF (here's a note with one: note1nvf6wm257sku94zt9dqaw439a67dg6qq8wwjh9xg2pny07rpvk8qp8xkcq)
4. Tap anywhere on the GIF to play the animation
5. Tap a GIF that's animating to view the GIF full screen
6. Double-tap to zoom in the full-screen viewer
7. Double-tap to zoom out
8. Tap the "X" button or swipe down to close the image viewer

[setch-l]

@joshuatbrown - When I follow the steps above on a mac - the gif auto-plays. On a phone I need to click it. I don't think this is a big issue so I'm going to continue the ticket forward.