Comment 4 for bug 1999068

I'm going to change my mind about the root cause. It appears that we simply forgot to check if the authorization has set the flag request.user_token_valid, which keystonemiddleware checks in AuthProtocol.process_request(). I copied the missing chunk to AuthContextMiddleware.process_request() and it cleared the problem.

See WIP patch https://review.opendev.org/c/openstack/keystone/+/874346