Bugfix: Infinite loop in beforeblur event (#19053)

* Failing test: Infinite loop in beforeblur event

If the focused node is hidden by a Suspense boundary, we fire the
beforeblur event. Our check for whether a tree is being hidden isn't
specific enough. It should only fire when the tree is initially hidden,
but it's being fired for updates, too.

* Only fire beforeblur on visible -> hidden

Should only beforeblur fire if the node was previously visible. Not
during updates to an already hidden tree.

To optimize this, we should use a dedicated effect tag and mark it in
the render phase. I've left this for a follow-up, though. Maybe can
revisit after the planned refactor of the commit phase.

* Move logic to commit phase

isFiberSuspenseAndTimedOut is used elsewhere, so I inlined the commit
logic into the commit phase itself.