Set items per query in notification manager back to real level

lib/services/notifications_manager.dart

@@ -20,7 +20,7 @@ import 'follow_requests_manager.dart';
 import 'network_status_service.dart';
 
 class NotificationsManager extends ChangeNotifier {
-  static const itemsPerQuery = 10;
+  static const itemsPerQuery = 50;
   static const minimumDmsAndCrsUpdateDuration = Duration(seconds: 30);
   static final _logger = Logger('NotificationManager');
   final Profile profile;