remove line after change

covas_mobile/lib/pages/MapboxPages.dart

@@ -52,6 +52,7 @@ class _MapboxPagesState extends State<MapboxPages> with ShowErrorDialog {
   bool isLoading = true;
   late LatLng userPosition;
   bool isUserPositionInitialized = false;
+  Line? currentRouteLine;
 
   @override
   void initState() {
@@ -223,6 +224,11 @@ class _MapboxPagesState extends State<MapboxPages> with ShowErrorDialog {
   }
 
   Future<void> _drawRouteAndMarkers() async {
+    // Remove previous route line if it exists
+    if (currentRouteLine != null) {
+      await mapController.removeLine(currentRouteLine!);
+      currentRouteLine = null;
+    }
     if (!isUserPositionInitialized) {
       showErrorDialog(
           context, "User position is not yet initialized. Try again.");
@@ -249,10 +255,10 @@ class _MapboxPagesState extends State<MapboxPages> with ShowErrorDialog {
       ));
 
       // Fetch and draw route
-      await _fetchRoute(userPosition!, destination, selectedMode);
+      await _fetchRoute(userPosition, destination, selectedMode);
 
       if (routeCoordinates.isNotEmpty) {
-        await mapController.addLine(
+        currentRouteLine = await mapController.addLine(
           LineOptions(
             geometry: routeCoordinates,
             lineColor: '#3b9ddd',
@@ -260,6 +266,7 @@ class _MapboxPagesState extends State<MapboxPages> with ShowErrorDialog {
             lineOpacity: 0.8,
           ),
         );
+
         _zoomToFitRoute(routeCoordinates);
       }
     } else {