Cannot Sign and Close experiments when a group only has one user

Cannot Sign and Close experiments when a group only has one user

When trying to sign and close and experiment there has to be someone to be able to witness the experiment, if the author is the only user in the group the application will throw an error.
In order to get around this we have to add another user (or copy a user reference) into the group, once another user is present the sign and close process will not be interrupted.