As a system, I can pass an url to an attachment instead of a base 64 file

For the "evidences" attachments, pass a file:// url, that contains the path to the file on the server (or something similar). e.g.

"evidences" : [

{ "dataURL": "file:///var/atlassian/application-data/shared/data/exploratory-testing-for-jira/scenario/0/s921/Step_9.jpg", "filename": "Step_9.jpg", "contentType": "image/jpeg" }

]