Some tests compare things to the output of `->to_api` and are exploding
because the (now mandatory) `user` parameter is not passed in the call.
In the case of IdP.t I just got rid of the use of `to_api` as we are
just trying to acknowledge a new user has been created and the API
representation of it is irrelevant.
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>