don't init UP on platforms other than Linux or Android

lib/controllers/unified_push.dart

@@ -21,6 +21,8 @@ import "package:window_manager/window_manager.dart";
 class UnifiedPushController extends AsyncNotifier<bool> {
   @override
   Future<bool> build() async {
+    if (Platform.isLinux ^ Platform.isAndroid) return false;
+
     final client = ref.watch(ClientController.provider.notifier);
     final registered = await UnifiedPush.initialize(
       linuxOptions: .new(