🔥(backend) remove users systematic return of profile_contact

Custom UserManaged returned profile_contact field when returning users.
While this may be useful later, we'd currently rather have it return users.

src/backend/core/tests/test_api_users.py

@@ -311,7 +311,6 @@ def test_api_users_retrieve_me_authenticated():
         "timezone": str(user.timezone),
         "is_device": False,
         "is_staff": False,
-        "data": user.profile_contact.data,
     }