Change part of the tests to use client_request

Two tests retained the old syntax because of mocker conflict:
when logging in as a user through client_request, it sets up a
side_effect on user_api_client.get_user to the user you log in
as. If you later want to set return_value for get_user to
something else, problems start :d.

app/templates/views/find-users/find-users-by-email.html

@@ -46,6 +46,6 @@
     </ul>
   </nav>
   {% elif users_found == [] %}
-    <p>No users found.</p>
+    <p class="browse-list-hint">No users found.</p>
   {% endif %}
 {% endblock %}