Core/Misc: Fix exploit

Fix exploit that allowed to duplicate stackable splitable items. If the item that cast the spell can't be found anymore, the spell is cancelled.

Fixes https://github.com/TrinityCore/TrinityCore/issues/11977
DB/Creature: Remove Trigger Flags on Chaotic Rift

By dr-j, closes #11988
Merge branch 'master' of github.com:TrinityCore/TrinityCore into 4.3.4