Change the auth challenge 401 to be verbose trace.

[TingluoHuang]

When the runner's OAuth token expired and needs a refresh, we log the following warning to the runner diag log.

[2022-07-25 17:34:28Z WARN GitHubActionsService] Authentication failed on first request with status code 401.
WWW-Authenticate: Bearer
Strict-Transport-Security: max-age=2592000
X-TFS-ProcessId: 994a3e77-7bca-4c4c-81e7-e72c37958c93
ActivityId: 74581e5a-cc7c-44c1-b42b-16ffab259bae
X-TFS-Session: 3865f3e2-07e8-4776-9ab5-bf3879b101be
X-VSS-E2EID: ccfcd2f9-2720-4519-a1e9-36405a46c125
X-VSS-SenderDeploymentId: 6bfa0b85-0342-b826-1c9f-bc636d8425af
X-TFS-ServiceError: The+user+%27System%3aPublicAccess%3baaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa%27+is+not+authorized+to+access+this+resource.
X-VSS-S2STargetService: 0000005A-0000-8888-8000-000000000000/visualstudio.com
X-Cache: CONFIG_NOCACHE
X-MSEdge-Ref: Ref A: CB6CE181CB5F4B41ACF055B51FB17F6C Ref B: ASHEDGE1308 Ref C: 2022-07-25T17:34:28Z
Date: Mon, 25 Jul 2022 17:34:28 GMT
Transfer-Encoding: chunked

This is not helpful to our customers other than creating confusion to make them think the runner is experiencing auth issue.

I am moving the particular trace into verbose from warning to avoid confusion.

[cory-miller]

LGTM