adding additional layer of check

Author: padhupradheep

nav2_behavior_tree/plugins/decorator/path_longer_on_approach.cpp

@@ -36,6 +36,7 @@ bool PathLongerOnApproach::isPathUpdated(
 {
   return old_path.poses.size() != 0 &&
          new_path.poses.size() != 0 &&
+         new_path.poses.size() != old_path.poses.size() &&
          old_path.poses.back().pose.position == new_path.poses.back().pose.position;
 }