What is the recommended way to check whether a saved access token is valid or not (e.g. a user may have revoked access via the website)?
I guess I am looking for the equivalent of the old HasLinkedAccount method...
Access tokens can be revoked remotely at any time, so the only way to check if it's still valid is to make an API call. The GetCurrentAccountAsync method is a good one for that, as it doesn't have any side effects.
(By the way, I believe the old HasLinkedAccount method you referred to didn't actually do that, and only checked for the local existence of an access token.)
