Update kernel

Add import profile via QR code image

lib/common/preferences.dart

@@ -1,7 +1,6 @@
 import 'dart:async';
 import 'dart:convert';
 
-import 'package:flutter/cupertino.dart';
 import 'package:shared_preferences/shared_preferences.dart';
 
 import '../models/models.dart';
@@ -29,8 +28,7 @@ class Preferences {
     try {
       return ClashConfig.fromJson(clashConfigMap);
     } catch (e) {
-      debugPrint(e.toString());
-      return null;
+      throw e.toString();
     }
   }
 
@@ -50,8 +48,7 @@ class Preferences {
     try {
       return Config.fromJson(configMap);
     } catch (e) {
-      debugPrint(e.toString());
-      return null;
+      throw e.toString();
     }
   }