Minor lag improvements to overworld animations

Data/Scripts/009_Scenes/002_EventScene.rb

@@ -162,6 +162,7 @@ class EventScene
       next if !sprite || sprite.disposed? || !sprite.is_a?(Sprite)
       sprite.update
     end
+    @usersprites.delete_if { |sprite| sprite.disposed? }
     @onUpdate.trigger(self)
     if Input.trigger?(Input::BACK)
       @onBTrigger.trigger(self)