run mock auth tests without azure creds

[djmitche]

Github Bug/Issue: Fixes #3503

[djmitche]

The decision task failed with

[task 2020-09-16T15:58:57.359Z] * method:     createTask
[task 2020-09-16T15:58:57.359Z] * errorCode:  MalformedPayload
[task 2020-09-16T15:58:57.359Z] * statusCode: 400
[task 2020-09-16T15:58:57.359Z] * time:       2020-09-16T15:58:57.324Z
[task 2020-09-16T15:58:57.362Z] 2020-09-16 15:58:57,362 - ERROR - Payload must be JSON with content-type: application/json got content-type: null

..trying again, but that seems a very odd intermittent!