Revert wsHost for ably (#8522)

Their website url has changed but the wsHost stays the same. Just tested and confirmed.

Author: modernben

broadcasting.md

@@ -229,7 +229,7 @@ window.Pusher = Pusher;
 window.Echo = new Echo({
     broadcaster: 'pusher',
     key: import.meta.env.VITE_ABLY_PUBLIC_KEY,
-    wsHost: 'realtime-pusher.ably.com',
+    wsHost: 'realtime-pusher.ably.io',
     wsPort: 443,
     disableStats: true,
     encrypted: true,