adding missing const

frontend/lib/modules/new_trip_button.dart

@@ -11,7 +11,7 @@ class NewTripButton extends StatefulWidget {
   final Trip trip;
   final UserPreferences preferences;
 
-  const NewTripButton({
+  const NewTripButton({super.key,
     required this.trip,
     required this.preferences,
     });
@@ -35,8 +35,8 @@ class _NewTripButtonState extends State<NewTripButton> {
         return FloatingActionButton.extended(
           onPressed: onPressed,
           icon: const Icon(Icons.directions),
-          label: AutoSizeText('Start planning!'),
-        ); 
+          label: const AutoSizeText('Start planning!'),
+        );
       }
     );
   }