Make getPickedItem() return null by default instead of air

src/entity/Entity.php

@@ -1563,7 +1563,7 @@ public function despawnFromAll() : void{
 	 * Returns the item that players will equip when middle-clicking on this entity.
 	 */
 	public function getPickedItem() : ?Item{
-		return VanillaItems::AIR();
+		return null;
 	}
 
 	/**