dillon1000/react

Bugfix: In legacy mode, call suspended tree's unmount effects when it is deleted (#24400)

* Bug: Missing unmount when suspended tree deleted

When a suspended tree switches to a fallback, we unmount the effects.
If the suspended tree is then deleted, there's a guard to prevent us
from unmounting the effects again.

However, in legacy mode, we don't unmount effects when a tree suspends.
So if the suspended tree is then deleted, we do need to unmount
the effects.

We're missing a check for legacy/concurrent mode.

* Fix: Unmount suspended tree when it is deleted