Circulation->Retrieve Recent Patrons can have duplicate entries

Branch for testing: https://git.evergreen-ils.org/?p=working/Evergreen.git;a=shortlog;h=refs/heads/user/dbriem/lp2009281_recent_patron_duplicates

Testing for bug squashing. With the "Number of Retrievable Recent Patrons" set to 2, I accessed two accounts and then clicked "Retrieve Last Patron." Where the previous behavior was that the patron would show up twice, now the entry is not duplicated, but the results only show the one patron, so it appears to still be counting both instances of opening the same account, instead of what I think is the desired behavior of showing both accounts that were accessed.

Testing on https://terran-master.gapines.org/

1. Set the "Number of Retrievable Recent Patrons" setting to 2.
2. Open a patron record from Patron Search
3. Open a second patron record from Patron Search
4. Go to Circulation->Retrieve Last Patron
5. Go to Circulation->Retrieve Recent Patrons and only the last patron displays.

Next test I searched and retrieved 4 patron records.
For this test I returned to the home screen.
I did Retrieve Last Patron which correctly retrieved my last patron.
I did Retrieve Recent Patrons and only the last patron displayed.

Removing pullrequest due to testing comments 2 & 3. (Note that for testing this was installed along with https://bugs.launchpad.net/evergreen/+bug/1901072 which has since been committed.)

Susan and Joan seem to have found another problem that applies to both the AngularJS and Angular interfaces.

The issue: user is added to the front of the list (ex. [A, A, B]), then the list is trimmed by 1 relative to the max setting ([A, A]), then 1 duplicate is removed ([A]).

This is related enough that I don't think it needs another bug. Branch for testing: https://git.evergreen-ils.org/?p=working/Evergreen.git;a=shortlog;h=refs/heads/user/dbriem/lp2009281_recent_patrons_duplicates

I have tested this code and consent to signing off on it with my name, Susan Morrison, and my email address, <email address hidden>.

Thanks, Dan and Susan! Pushed to rel_3_10 and above.