Do not allow swapping an opened GUI item (i.e. terminals) out of the off-hand slot (#8593)

Fixes potential loss of item or dupes

Fixes #8257

Author: shartte

src/main/java/appeng/menu/AEBaseMenu.java

@@ -42,6 +42,7 @@
 import net.minecraft.world.entity.player.Inventory;
 import net.minecraft.world.entity.player.Player;
 import net.minecraft.world.inventory.AbstractContainerMenu;
+import net.minecraft.world.inventory.ClickType;
 import net.minecraft.world.inventory.MenuType;
 import net.minecraft.world.inventory.Slot;
 import net.minecraft.world.item.ItemStack;
@@ -212,6 +213,16 @@ protected final void createPlayerInventorySlots(Inventory playerInventory) {
         }
     }
 
+    @Override
+    public void clicked(int slotId, int button, ClickType clickType, Player player) {
+        // Do not allow swapping with off-hand if the off-hand slot is locked
+        if (clickType == ClickType.SWAP && isPlayerInventorySlotLocked(Inventory.SLOT_OFFHAND)) {
+            return;
+        }
+
+        super.clicked(slotId, button, clickType, player);
+    }
+
     protected Slot addSlot(Slot slot, SlotSemantic semantic) {
         slot = this.addSlot(slot);