Update planning/autoware_path_generator/src/utils.cpp

Signed-off-by: Junya Sasaki <junya.sasaki@tier4.jp>

Co-authored-by: Mitsuhiro Sakamoto <50359861+mitukou1109@users.noreply.github.com>

planning/autoware_path_generator/src/utils.cpp

@@ -524,11 +524,7 @@ std::optional<lanelet::ConstLanelets> extract_lanelets_from_path(
       int64_t lane_id = path_point.lane_ids.at(0);
       lanelet::ConstLanelet lanelet = planner_data.lanelet_map_ptr->laneletLayer.get(lane_id);
 
-      const bool is_unique =
-        std::find(refined_path_lanelets.begin(), refined_path_lanelets.end(), lanelet) ==
-        refined_path_lanelets.end();
-
-      if (is_unique) {
+      if (!exists(refined_path_lanelets, lanelet)) {
         refined_path_lanelets.push_back(lanelet);
       }
     } catch (const std::out_of_range & e) {