Returns whether an inventory item is locked, usually as it awaits pending action.
isLocked = IsInventoryItemLocked(slotId)
- number - The slot ID used to refer to that slot in the other GetInventory functions.
- boolean - 1 if the slot is locked, nil otherwise
- PickupInventoryItem on an empty slot will not lock that slot.
- PickupInventoryItem on the ammo slot will not lock that slot.