fix config update issue

lib/foundation/comic_source/parser.dart

@@ -157,9 +157,11 @@ class ComicSourceParser {
 
     await source.loadData();
 
+    if(_checkExists("init")) {
       Future.delayed(const Duration(milliseconds: 50), () {
         JsEngine().runCode("ComicSource.sources.$_key.init()");
       });
+    }
 
     return source;
   }

lib/pages/comic_source_page.dart

@@ -55,10 +55,10 @@ class ComicSourcePage extends StatefulWidget {
       title: "Updates Available".tl,
       content: msg,
       confirmText: "Update",
-      onConfirm: () {
+      onConfirm: () async {
         for (var key in shouldUpdate) {
           var source = ComicSource.find(key);
-          _BodyState.update(source!);
+          await _BodyState.update(source!);
         }
       },
     );
@@ -277,7 +277,7 @@ class _BodyState extends State<_Body> {
     }
   }
 
-  static void update(ComicSource source) async {
+  static Future<void> update(ComicSource source) async {
     if (!source.url.isURL) {
       App.rootContext.showMessage(message: "Invalid url config");
       return;