Creative mode itemDropThreshold is not considered in all situations

The bug

Creative mode has an item drop threshold (NetHandlerPlayServer.itemDropThreshold), but the problem is that this is not considered for all cases.

Currently it is only used when the player throws item out of the creative inventory tabs or when the "Survival Inventory" is open. Other cases like throwing items from the hotbar, or items created when interacting with entities, containers are closed, etc. are not considered.

How to reproduce

1. Put items in your hotbar
2. Close your inventory
3. Try dropping the items from the hotbar as fast as possible
   → All items are successfully thrown, the treshold was not considered