Hi Daniel,
Thanks so much for reaching out and thank you for using Cloud WordPress for your staging needs. Unfortunately the user authentication you are referring to is native to WordPress and we aren’t able to remove the authentication requirement for anything that would normally require a login.
When Staging a site with Cloud WordPress you are able to publish posts or pages as publicly visible if you want what you are trying to share to be publicly accessible to your client. If that’s a good option you can just share the link with your client.
If you need your client to access the Admin Dashboard without being prompted for a login there isn’t a way to do this without the help of a plugin. A good one for this that you might consider is the Temporary Login without Password plugin. You can use that plugin to generate a temporary login for your client and provide them whatever level of access as necessary. After the login is created just send your client the link generated by the plugin and they will be able to access your WordPress admin area as if they were logged in.
I hope this helps! Please reach back out if there’s anything else that we can answer for you.