Improve Logic in Twistlock Scan

Current Behavior

The Twistock scan job within the Scanning stage may output a JSON file with an empty Vulnerabilities list and a value in the err field.

Live Example

https://repo1.dsop.io/dsop/redhat/ubi/ubi8/-/pipelines/105250 https://repo1.dsop.io/dsop/opensource/goharbor/harbor-db/-/pipelines/105223

Viewing the twistlock_cve.json file for these runs shows that the have empty vulnerability lists and an error message in the err field that contains Failed to pull image

Expected Behavior

Logic to handle an error message in the err field

Possible Solution

When an error exists either attempt the scan again a set number of times and then fail, or fail immediately.