fix unmount cycle of toast component

[arthur-lemeur]

Fixes #3448

[panaC]

Good, but doesn't fix the issue

[danielweck]

Good, but doesn't fix the issue

@panaC , @arthur-lemeur pushed another commit, does it work now?

[danielweck]

@panaC will you have time early this week to confirm that this PR works? It would be great to fix the bug in 3.4.0

[panaC]

@danielweck There is still an issue with the transitionend event may not fire in some cases.
It would be more robust to handle all related transition events, including transitionrun, transitionstart, and transitioncancel.
Currently, the toast removal logic relies solely on the transitionend event. If this event is not triggered, a div overlay can block interaction with the settings button (except near its border).
To make this more reliable, I think it would be safer to include a fallback mechanism like a timeout, to ensure the toast state stays in sync with the UI.

[panaC]

See my last message.