Add PlayerUseUnknownEntityEvent

Adds the PlayerUseUnknownEntityEvent to be used by plugins dealing with
virtual entities/entities that are not actually known to the server.

Co-authored-by: Nassim Jahnke <nassim@njahnke.dev>

paper-server/src/main/java/org/bukkit/craftbukkit/event/CraftEventFactory.java

@@ -1929,4 +1929,13 @@ public class CraftEventFactory {
 
         Bukkit.getPluginManager().callEvent(new EntityRemoveEvent(entity.getBukkitEntity(), cause));
     }
+    // Paper start - PlayerUseUnknownEntityEvent
+    public static void callPlayerUseUnknownEntityEvent(net.minecraft.world.entity.player.Player player, net.minecraft.network.protocol.game.ServerboundInteractPacket packet, InteractionHand hand, @Nullable net.minecraft.world.phys.Vec3 vector) {
+        new com.destroystokyo.paper.event.player.PlayerUseUnknownEntityEvent(
+            (Player) player.getBukkitEntity(), packet.getEntityId(), packet.isAttack(),
+            CraftEquipmentSlot.getHand(hand),
+            vector != null ? CraftVector.toBukkit(vector) : null
+        ).callEvent();
+    }
+    // Paper end - PlayerUseUnknownEntityEvent
 }