Proxy: Can Add Myself as a Own Proxy

Steps to repro:

1. Log into folio-snapshot-stable as diku_admin
2. Edit a user
3. Change their last name to start with A and note their patron group
4. Go down to the proxy section and add a new proxy user
5. Add this user as a proxy for themselves (or sponsor) BUT don't do it by searching for their name in the user search and select popup (there is a bug with this right now UIU-731). Find them by filtering on their patron group and then sorting by name. Since you changed their name to begin with A, they should be at the top.
6. Save the record
7. Saves fine
8. Edit the record

Expected: You shouldn't be able to add yourself as proxy or sponsor for yourself. I doubt if this was every prevented. It was probably not in the original user story scenarios. What would be the easiest way to prevent this? Not show the current record in the search and select popup? Display an error if you try to select the current user as a proxy or sponsor?

Actual: The user is now showing as both proxy AND sponsor for themselves