add carton editor for mix carton

lib/app.dart

@@ -29,6 +29,7 @@ import 'package:flutter/material.dart';
 import 'package:flutter_localizations/flutter_localizations.dart';
 import 'package:provider/provider.dart';
 
+import 'pages/carton/model/carton_selection_model.dart';
 import 'pages/delivery/model/delivery_model.dart';
 
 class App extends StatefulWidget {
@@ -62,6 +63,7 @@ class _AppState extends State<App> {
   final CartonSizeModel cartonSizeModel = new CartonSizeModel();
   final ProcessingModel processingModel = new ProcessingModel();
   final PickupModel pickupModel = new PickupModel();
+  final CartonSelectionModel cartonSelectionModel = new CartonSelectionModel();
 
   late AppTranslationsDelegate _newLocaleDelegate;
 
@@ -84,7 +86,8 @@ class _AppState extends State<App> {
       ..addModel(deliveryModel)
       ..addModel(cartonSizeModel)
       ..addModel(processingModel)
-      ..addModel(pickupModel);
+      ..addModel(pickupModel)
+      ..addModel(cartonSelectionModel);
 
     _newLocaleDelegate = AppTranslationsDelegate(
         newLocale: Translation().supportedLocales().first);
@@ -133,6 +136,7 @@ class _AppState extends State<App> {
           ChangeNotifierProvider.value(value: cartonSizeModel),
           ChangeNotifierProvider.value(value: processingModel),
           ChangeNotifierProvider.value(value: pickupModel),
+          ChangeNotifierProvider.value(value: cartonSelectionModel),
         ],
         child: Consumer<LanguageModel>(
           builder: (context, value, child) {