dillon1000/react

[Fiber] Support only View Transitions v2 (#31996)

Stacked on #31975.

We're going to recommend that the primary way you style a View
Transition is using a View Transition Class (and/or Type). These are
only available in the View Transitions v2 spec. When they're not
available it's better to fallback to just not animating instead of
animating with the wrong styling rules applied.

This is already widely supported in Chrome and Safari 18.2. Safari 18.2
usage is still somewhat low but it's rolling out quickly as we speak.

A way to detect this is by just passing the object form to
`startViewTransition` which throws if it's an earlier version. The
object form is required for `types` but luckily classes rolled out at
the same time. Therefore we're only indirectly detecting class support.

This means that in practice Safari 18.0 and 18.1 won't animate. We could
try to only apply the feature detection if you're actually using classes
or types, but that would create an unfortunate ecosystem burden to try
to support names. It also leads to flaky effects when only some
animations work. Better to just disable them all.

Firefox has yet to ship anything. We'll have to look out for how the
feature detection happens there and if they roll things out in different
order but if you ship late, you deal with web compat as the ball lies.