ORA: document process for locating a particular student submission

Enhancement to doc on removing ORA submissions. If a student alerts an instructor to a problematic assignment, instructors need PM help to identify the response.

Per : the course team should ask the reporter to send a snippet of the offending post to the course team then, unfortunately for now, they need to request a data download of all ORA responses from their PM, who will get it from devops. Then they can search that spreadsheet for the offending post, and get the username from there.
When we implement ORA data downloads from the instructor dash, this will be much easier