Fixes Lava Duplication Glitch (#1964)

Due to the fact, that Obsidian Scooping uses one tick delay to remove obsidian, a player with a bucket in hand and offhand duplicated lava. 
To avoid that, added an extra check that ignores the interact event if a player holds a bucket in both hands, and interacted hand is offhand.

Fixes #1963

src/main/java/world/bentobox/bentobox/listeners/flags/worldsettings/ObsidianScoopingListener.java

@@ -15,6 +15,7 @@
 import org.bukkit.event.EventPriority;
 import org.bukkit.event.block.Action;
 import org.bukkit.event.player.PlayerInteractEvent;
+import org.bukkit.inventory.EquipmentSlot;
 import org.bukkit.inventory.ItemStack;
 
 import world.bentobox.bentobox.BentoBox;
@@ -54,6 +55,16 @@ boolean onPlayerInteract(final PlayerInteractEvent e) {
                 || e.getClickedBlock().getRelative(e.getBlockFace()).getType().equals(Material.WATER)) {
             return false;
         }
+
+        if (Material.BUCKET.equals(e.getPlayer().getInventory().getItemInOffHand().getType()) &&
+            Material.BUCKET.equals(e.getPlayer().getInventory().getItemInMainHand().getType()) &&
+            EquipmentSlot.OFF_HAND.equals(e.getHand()))
+        {
+            // If player is holding bucket in both hands, then allow to interact only with main hand.
+            // Prevents lava duplication glitch.
+            return false;
+        }
+
         return lookForLava(e);
     }