Update autoware_system_designer/autoware_system_designer/visualization/js/node_diagram.js

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: technolojin

autoware_system_designer/autoware_system_designer/visualization/js/node_diagram.js

@@ -501,7 +501,11 @@ class NodeDiagramModule extends DiagramBase {
       e.stopPropagation();
       this.updateInfoPanel(userData, "Node");
       this.clearHighlights();
-      g.classList.add("highlighted");
+      if (node.children?.length) {
+        this.highlightModule(node, g);
+      } else {
+        g.classList.add("highlighted");
+      }
 
       const outwardInPortIds = (userData.in_ports || [])
         .filter((p) => p.unique_id && p.is_outward !== false)