Fix follow request count to dynamically update (#16652)

app/javascript/mastodon/actions/notifications.js

 import api, { getLinks } from '../api';
 import IntlMessageFormat from 'intl-messageformat';
-import { fetchRelationships } from './accounts';
+import { fetchFollowRequests, fetchRelationships } from './accounts';
 import {
   importFetchedAccount,
   importFetchedAccounts,
@@ -78,6 +78,10 @@ export function updateNotifications(notification, intlMessages, intlLocale) {
       filtered = regex && regex.test(searchIndex);
     }
 
+    if (['follow_request'].includes(notification.type)) {
+      dispatch(fetchFollowRequests());
+    }
+
     dispatch(submitMarkers());
 
     if (showInColumn) {