adding missing const

frontend/lib/utils/fetch_trip.dart

@@ -21,7 +21,7 @@ Dio dio = Dio(
     validateStatus: (status) => status! <= 500,
     receiveDataWhenStatusError: true,
     contentType: Headers.jsonContentType,
-    responseType: ResponseType.json,    
+    responseType: ResponseType.json,
   ),
 );
 
@@ -32,7 +32,7 @@ fetchTrip(
 ) async {
   Map<String, dynamic> data = {
     "preferences": preferences.toJson(),
-    "start": trip.landmarks!.first.location,
+    "start": trip.landmarks.first.location,
   };
   String dataString = jsonEncode(data);
   log(dataString);
@@ -45,7 +45,7 @@ fetchTrip(
     );
   } catch (e) {
     trip.updateUUID("error");
-      
+
     // Format the error message to be more user friendly
     String errorDescription;
     if (e is DioException) {
@@ -93,7 +93,7 @@ fetchTrip(
     // Actualy no need to throw an exception, we can just log the error and let the user retry
     // throw Exception(errorDetail);
   } else {
-    
+
     // if the response data is not json, throw an error
     if (response.data is! Map<String, dynamic>) {
       log("${response.data.runtimeType}");
@@ -142,7 +142,7 @@ patchLandmarkImage(Landmark landmark) async {
     // the image is a google photos link, we should get the image behind the link
     String? newUrl = await getImageUrlFromGooglePhotos(landmark.imageURL!);
     // also set the new url if it is null
-    landmark.imageURL = newUrl; 
+    landmark.imageURL = newUrl;
   }
 }