Make moveit_servo listen to Octomap updates (backport moveit#2601) (moveit#2606)

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Co-authored-by: Amal Nanavati <amaln@cs.washington.edu>
(cherry picked from commit 87d5945)

Author: mergify[bot]

moveit_ros/moveit_servo/src/servo_node.cpp

@@ -90,6 +90,7 @@ ServoNode::ServoNode(const rclcpp::NodeOptions& options)
       node_, robot_description_name, "planning_scene_monitor");
   planning_scene_monitor_->startStateMonitor(servo_parameters->joint_topic);
   planning_scene_monitor_->startSceneMonitor(servo_parameters->monitored_planning_scene_topic);
+  planning_scene_monitor_->startWorldGeometryMonitor();
   planning_scene_monitor_->setPlanningScenePublishingFrequency(25);
   planning_scene_monitor_->getStateMonitor()->enableCopyDynamics(true);
   planning_scene_monitor_->startPublishingPlanningScene(planning_scene_monitor::PlanningSceneMonitor::UPDATE_SCENE,