[Media Display] Create a broken link view

[joshuatbrown]

When a media link is broken, we want to show a broken link view. We have multiple designs for the icon, but we can create the placeholder and temporarily use any of the icons until we've decided which one to use long-term.

https://www.figma.com/design/s0qf4VmyQygydP8MIQazZc/Nos?node-id=7967-1058&t=fir2ak9acdqbsqF0-4

[joshuatbrown]

This is done as designed (#1589 -- not merged yet) but in order to finish it, I'd like to use a different design that's less likely to impact performance. See comment in Figma.

[joshuatbrown]

@setch-l to test this, you can create a note with a link to an image that doesn't exist, such as http://example.com/no.png and then view the note.