Fix ObserverTracerListener

Signed-off-by: yoyosource <yoyosource@nidido.de>

BauSystem_Main/src/de/steamwar/bausystem/features/observer/ObserverTracerListener.java

@@ -47,6 +47,9 @@ public class ObserverTracerListener implements Listener {
 
     @EventHandler
     public void onPlayerInteract(PlayerInteractEvent event) {
+        if (event.getMaterial() == Material.OBSERVER) {
+            return;
+        }
         if (event.getAction() != Action.RIGHT_CLICK_BLOCK) {
             return;
         }