fix for split (#2)

* split authenticate into separate overridable function

* cleaner exception

* basic unit test

* remove new test

* space to revert change

* return the user

Author: marcelkornblum

djangosaml2/views.py

@@ -605,6 +605,8 @@ def authenticate_user(
         self.post_login_hook(request, user, session_info)
         self.customize_session(user, session_info)
 
+        return user
+
     def post_login_hook(
         self, request: HttpRequest, user: settings.AUTH_USER_MODEL, session_info: dict
     ) -> None: