FAPI tests:check acr_values_supported
As per FAPI WG ticket here:
https://bitbucket.org/openid/fapi/issues/249/certification-clarification-request
we should verify that the following are present in acr_values_supported
in the discovery document:
- Any acr value we request
- Any acr value returned from the server (in the
id_token
acr
claim)
Any failure must just be a 'warning' as there's no normative text that requires all supported acr values to be listed in the server metadata.