🚨 Fix meta import warning for CodeFactor

Author: AlexV525

example/lib/constants/page_mixin.dart

@@ -14,7 +14,6 @@ import '../widgets/method_list_view.dart';
 import '../widgets/selected_assets_list_view.dart';
 import 'picker_method.dart';
 
-@optionalTypeArgs
 mixin ExamplePageMixin<T extends StatefulWidget> on State<T> {
   final ValueNotifier<bool> isDisplayingDetail = ValueNotifier<bool>(true);
 

example/lib/pages/multi_assets_page.dart

@@ -14,7 +14,7 @@ class MultiAssetsPage extends StatefulWidget {
 }
 
 class _MultiAssetsPageState extends State<MultiAssetsPage>
-    with AutomaticKeepAliveClientMixin, ExamplePageMixin {
+    with AutomaticKeepAliveClientMixin, ExamplePageMixin<MultiAssetsPage> {
   @override
   int get maxAssetsCount => 9;
 

example/lib/pages/single_assets_page.dart

@@ -15,7 +15,7 @@ class SingleAssetPage extends StatefulWidget {
 }
 
 class _SingleAssetPageState extends State<SingleAssetPage>
-    with AutomaticKeepAliveClientMixin, ExamplePageMixin {
+    with AutomaticKeepAliveClientMixin, ExamplePageMixin<SingleAssetPage> {
   @override
   int get maxAssetsCount => 1;