Svelte 5: Outro transition easing isn't reversed when it beings running before the intro transition is run

[aradalvand]

Describe the bug

A continuation (or "slice") of #9937.
Thanks to #10190, outro transitions have been fixed now in terms of easing (i.e. the easing is reversed, just like in Svelte 4), but only when they are triggered after the intro transition has finished — in the video below, notice how the outro transition begins fast and ends slowly (which is what cubicOut represents); this is correct:

Rec.0011.mp4

But if the outro transition is triggered before the intro transition has finished, the easing doesn't look the same, and suffers from the same issue that was described in #9937 — notice how this time the outro transition beings slowly and ends fast (which is the opposite of what a cubicOut animation is supposed to look like):

Rec.0012.mp4

Reproduction

The same REPL that was provided in #9937

Logs

No response

System Info

N/A

Severity

blocking an upgrade

[trueadm]

See #10220, let me know if that works for you.