dillon1000/react

[Fizz] Block on Suspensey Fonts during reveal (#33342)

This is the same technique we do for the client except we don't check
whether this is newly created font loading to keep code small.

Unfortunately, we can't use this technique for Suspensey images. They'll
need to block before we call `startViewTransition` in a separate
refactor. This is due to a bug in Chrome where `img.decode()` doesn't
resolve until `startViewTransition` does.