refreshCredential
Call to refresh a credential with a stored refresh token (that was received when issuing the credential for the first time, stored with storeRefreshToken).
Will request a new access token, and use that token to request the same credential again and store it.
Prefers building the token request by using scope (from SupportedCredentialFormat), as advised in OpenID4VC HAIP, but falls back to authorization details if needed.