Enable ESLint no-useless-escape (#23311)

app/javascript/mastodon/actions/push_notifications/registerer.js

@@ -8,7 +8,7 @@ import { me } from '../../initial_state';
 const urlBase64ToUint8Array = (base64String) => {
   const padding = '='.repeat((4 - base64String.length % 4) % 4);
   const base64 = (base64String + padding)
-    .replace(/\-/g, '+')
+    .replace(/-/g, '+')
     .replace(/_/g, '/');
 
   return decodeBase64(base64);