Users using smartcards with SAN extensions should be able to login
into gitlab, on the following two scenarios:

* The user certificate only has one email entry in the SAN extensions
  and it should be used to login into gitlab.
* The user certificate has multiple email entries and should only use
  the one that match the URI as described here
  https://docs.gitlab.com/ee/administration/auth/smartcard.html#authentication-against-a-local-database-with-x509-certificates-and-san-extensions-premium-only