Map duplication by using slot shortcuts

The bug

Maps can be duplicated by taking them out of the cartography table GUI by using the hotbar keyboard shortcuts.

To reproduce

1. Create a new map
2. Put it into a cartography table
3. Put an empty map into the second slot
4. Hover with the mouse over the slot with the map copies
5. Press number keys to put the maps into your hotbar slots
   → The maps from the cartography table input slots are not removed, thus duplicating the maps