Validate settings before saving

[rolodato]

Entering invalid settings such as a mistyped client ID, secret or tenant can cripple a Wordpress installation, since it breaks the login. These settings should be validated before saving to ensure the login configuration is always in a valid state.

[woloski]

@glena this one also

[glena]

To validate the client_id and secret, I am making this request (oauth/token) https://docs.auth0.com/api#!#post--oauth-token

Is it ok or there is another API call better suited for this?

[mgonto]

Works great :)