Refactor app initializer to use async function

Simplifies the app initializer by making it an async function directly instead of returning an async IIFE. This improves readability and maintains the same initialization behavior.

npm/ng-packs/packages/core/src/lib/providers/core-module-config.provider.ts

@@ -106,14 +106,11 @@ export function provideAbpCore(...features: CoreFeature<CoreFeatureKind>[]) {
         headerName: 'RequestVerificationToken',
       }),
     ),
-    provideAppInitializer(() => {
+    provideAppInitializer(async () => {
       inject(LocalizationService);
       inject(LocalStorageListenerService);
       inject(RoutesHandler);
-
-      return (async (): Promise<void> => {
-        await getInitialData();
-      })();
+      await getInitialData();
     }),
     LocaleProvider,
     CookieLanguageProvider,