Fix/ Venue: read review and comment readers from right invitations

[celestemartinez]

Sherry reported an issue when a paper is flagged for Ethics Review. It looks like the we were reading the review readers from the wrong place. I am now reading it from the review invitation itself instead of the ethics flag invitation.

[celestemartinez]

There are new changes here:

I save the reviewer and AE checklist names in the ARR ethics flag invitation to process these invitations as well in the Ethics_Flag process function. I deleted the ARR specific process function since it's no longer needed.

cc @haroldrubio