fix(goal_planner): fix detection_polygons visualiztion (#5596)

Author: kosuke55

planning/behavior_path_planner/src/scene_module/goal_planner/goal_planner_module.cpp

@@ -1752,16 +1752,16 @@ void GoalPlannerModule::setDebugData()
       "map", rclcpp::Clock{RCL_ROS_TIME}.now(), "detection_polygons", 0, Marker::LINE_LIST,
       tier4_autoware_utils::createMarkerScale(0.01, 0.0, 0.0),
       tier4_autoware_utils::createMarkerColor(0.0, 0.0, 1.0, 0.999));
-
+    const double ego_z = planner_data_->self_odometry->pose.pose.position.z;
     for (const auto & ego_polygon : debug_data_.ego_polygons_expanded) {
       for (size_t ep_idx = 0; ep_idx < ego_polygon.outer().size(); ++ep_idx) {
         const auto & current_point = ego_polygon.outer().at(ep_idx);
         const auto & next_point = ego_polygon.outer().at((ep_idx + 1) % ego_polygon.outer().size());
 
         marker.points.push_back(
-          tier4_autoware_utils::createPoint(current_point.x(), current_point.y(), 0.0));
+          tier4_autoware_utils::createPoint(current_point.x(), current_point.y(), ego_z));
         marker.points.push_back(
-          tier4_autoware_utils::createPoint(next_point.x(), next_point.y(), 0.0));
+          tier4_autoware_utils::createPoint(next_point.x(), next_point.y(), ego_z));
       }
     }
     debug_marker_.markers.push_back(marker);