Don't set reset observer callback

Author: sjahr

moveit_core/planning_scene/src/planning_scene.cpp

@@ -1214,9 +1214,6 @@ void PlanningScene::decoupleParent()
         (object_types_.value())[it->first] = it->second;
     }
   }
-
-  setCollisionObjectUpdateCallback(nullptr);
-
   parent_.reset();
 }