Transition + slots + #if

[yazonnile]

Describe the bug
If we update state while transition, #if statement inside transition element doesn't work with slots properly

To Reproduce

1. open REPL example
2. Click once on TOGGLE button
3. Slot elements inside element without transition works good. With transition - not
4. setTimeout just emulates state change close to transition end.

Expected behavior
With and without transition slots should work good

[halfnelson]

I wonder if this is caused by the same problem as
#3685

[yazonnile]

@halfnelson
looks very similar, agree

[halfnelson]

I can repro without slots
https://svelte.dev/repl/efc4d7292a6549e888c4a0ab98807e61?version=3.16.0

so I feel it is more likely the same problem, local "transition_in" on inner if block "end"ing a global outro which means the "on outro complete" callbacks aren't called which means the destroy is never called on the other part of the if

[halfnelson]

Just tested to see if #4634 fixed it. No such luck, can still reproduce with
https://svelte.dev/repl/efc4d7292a6549e888c4a0ab98807e61?version=3.22.3

[dummdidumm]

This is fixed in Svelte 5