Tempest assert wrong exception when validating service token

[bryan]

We are running OpenStack Zed and Antelope version, in test case "tempest.scenario.test_server_volume_attachment.TestServerVolumeAttachmentScenario", I called OpenStack volume detach API when an invalid token, it returns 401 to me, here it is:

curl -g -i -X DELETE http://10.250.21.200:8774/v2.1/servers/6ff1e2bc-c217-4644-966b-806bed2d8b62/os-volume_attachments/58912c35-6ada-4b70-9270-964faf3905f4 -H "Accept: application/json" -H "OpenStack-API-Version: compute 2.92" -H "User-Agent: python-novaclient" -H "X-Auth-Token: gAAAAABloY4PTFppEBWxft0hhBtN0rLAM-LEN0-QI5UnkhHQ60mXwiemez0WG9oy6gbYyXp5gzaSgVwW_LL290elqUDARHMQ7crhHNgjjdgosHai8JMPni4pk-i7PLcaCfTRvfp5ayHNczJaKTMIwKdfbdsTpgsZ_QSX23ADvWuVEVlU12PZ5iI1111" -H "X-OpenStack-Nova-API-Version: 2.93"
HTTP/1.1 401 Unauthorized
date: Fri, 12 Jan 2024 19:15:36 GMT
server: Apache
www-authenticate: Keystone uri="http://10.250.21.200:5000"
content-length: 114
x-openstack-request-id: req-3ad4eef4-eff0-4d1f-8f01-dab3d398189c
x-compute-request-id: req-3ad4eef4-eff0-4d1f-8f01-dab3d398189c
content-type: application/json

{"error": {"code": 401, "title": "Unauthorized", "message": "The request you have made requires authentication."}}

However, the test case is expecting [exceptions.Forbidden, exceptions.Conflict] when the token is invalid, this is not the same return with the actual result.

Here is a samilar patch: https://review.opendev.org/c/openstack/tempest/+/893334