dillon1000/react

[Fiber] Detect useSyncExternalStore mutations missed while Activity tree was hidden (#36947)

Fixes #27670.

When an Activity subtree is hidden, its passive effects are
disconnected, which unsubscribes from the store. On reveal, the effects
are reconnected by replaying the fiber's effect list without a render,
but if `updateStoreInstance` was not in the effect list then the
component would be left stale. This happened both when a layout effect
mutated the store during the reveal commit (after the subtree rendered
but before it resubscribed) and when the store changed while hidden and
the component bailed out of rendering during the reveal.

We now push the updateStoreInstance effect unconditionally but tag it
with HookHasEffect only under the same conditions as before, so regular
commits skip it when nothing changed but reconnection always triggers it
so it can trigger a rerender if appropriate.