Cannot get Keycloak to correctly act as an Identity broker when WS-Fed is used as the protocol about keycloak-wsfed HOT 2 CLOSED

From the user documentation, the first broker login flow is the correct first flow, as keycloak needs to create information for the user locally, and a link to the user in the external IdP, so the "browser" login flow shouldn't be investigated.

Now, for the first broker login flow, the problem is that when the username or Id is null, keycloak cannot create the link to the external IdP user due to the fields being null. The pull request from @SebZal corrects the Id problem, but not the username problem. Even through this can be avoided by configuring the client correctly in the IdP, the following steps will be taken:

• Make the getUsername() method return getId() if it can't get a name rather then the opposite. This will bring it in line for what is done for SAML2 tokens.
• Have the WSFedEndpoint handleLoginResponse method throw an exception if the Id or Username is null rather than waiting to get a NullPointerException to happen when keycloak tries to create the user's Identity Provider link.
• Write the unit tests for the SAML11RequestedToken class since there doesn't seem to be any :-p

from keycloak-wsfed.

Modifications done and tested

from keycloak-wsfed.