Fix link to browser configuration guide on Login page
There is a mismatch between 'i18n' krb_auth_msg and 'LoginScreen'
widget kerberos_msg. The former links to "unauthorized.html", but the latter
to "ssbrowser.html". Both should link to "ssbrowser.html" page.
Fixes: https://pagure.io/freeipa/issue/7624
Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>