"Sort results by barcode" does not sort properly

Overview:

When testing MCL sorting in the request app, testers encountered a situation when sorting by barcode where requests without a user barcode were not sorting correctly (interspersed with other request where a patron barcode value was present.

Steps to Reproduce:

1. Log into some Juniper Bugfest
2. Go to the Requests app
3. Filter by request status "Closed - Cancelled"
4. Attempt to sort the results descending by "Requester Barcode"

Expected Results:

Results are sorted, descending, by requester barcode, with empty values sorted appropriately.

Actual Results:

Records with empty requester barcode values are intermixed with records where a requester  barcode is present.

Additional Information:

May be worth taking a look at the general sort accuracy, as well, just to make sure.

URL: https://bugfest-juniper.folio.ebsco.com/requests/view/a1e7d32a-2ac3-41b7-a1d0-fe85cf0cf427?filters=requestStatus.Open%20-%20Not%20yet%20filled%2CrequestStatus.Open%20-%20Awaiting%20pickup%2CrequestStatus.Closed%20-%20Cancelled&mode=duplicate&sort=-requesterBarcode%2CrequestDate

Interested parties:

brookstravis MarynaZhuravlova