Reserve item - unable to remove temporary location (regression)

Overview:  A user should be able to remove the temporary location  from an item that is on reserve, and have that temporary location removed from both the reserve record and the instance/item record.  Currently they can change the temporary location to another temporary location, and remove it from the UI but not the json.

Use case:
As a staff user I want to run report on my use of Course reserves item. Reports are run on the raw json data in Courses.

Steps to Reproduce:

1. Log into FOLIO Snapshot environment as User Diku_Admin
2. Go to the Courses app, and find a course with a reserve item that has a temporary location assigned (or create one if there isn't any)
3. Select the edit reserve action
4. In the "Temporary location" box - select (None required) 
5. Click save and close
6. Note - the value in the temporary location field can be changed to a different location and be deleted
7. When viewing the json the item record data is not updated to be deleted.

Expected Results:
Removing the temporary location from an item in the item record would remove the temporary location from both the Reserve record and the inventory/item record, and this is verified in both the UI and in the json

Actual Results:
Nothing changes in the json

Additional Information: This bug is also present in FOLIO Bugfest Iris https://bugfest-iris.folio.ebsco.com/cr/courses?sort=name

One additional thing about this bug that is very confusing has to do with the UI in Courses View. So if you have an item where you want to remove the temporary location, you could remove the location in the Inventory item record, and then go back into Courses and look at the reserve record on the course and see that it has the temporary location, and think you've actually removed it. You haven't, though, because the underlying reserve record still has a temporaryLocationId set.

Example on FOLIO Iris (I can recreate this scenario in whatever environment it's needed in):

Screenshot of an item being viewed on the Course with temporaryLocationId blank:

Underlying reserve record where you can see that temporaryLocationId has a value:

        {
            "id": "205f3e15-5318-4732-8aa4-bd9bc54bf32b",
            "courseListingId": "3e25c33b-e21d-45b5-a672-b3c19b0dca5d",
            "itemId": "c34c124f-61bf-4066-9757-da8ebdfc2ac2",
            "startDate": "2020-01-19",
            "endDate": "2020-03-14",
            "copiedItem": {
                "barcode": "erin-barcode",
                "temporaryLocationId": "53cf956f-c1df-410b-8bea-27f712cca7c0",
                "permanentLocationId": "f34d27c6-a8eb-461b-acd6-5dea81771e70",
                "title": "Erin's test record",
                "contributors": [],
                "publication": [],
                "instanceId": "9635d405-194e-46f0-9803-1eef3881972e",
                "instanceHrid": "in00000000007",
                "holdingsId": "01cbd51c-aebd-4ddd-a4d3-d174e607a094"
            },
            "metadata": {
                "createdDate": "2021-05-21T15:38:10.020+00:00",
                "createdByUserId": "6cd2c503-1146-5769-90bc-9557ed6ce97b",
                "updatedDate": "2021-05-21T16:34:30.212+00:00",
                "updatedByUserId": "6cd2c503-1146-5769-90bc-9557ed6ce97b"
            }
        }

URL:
Interested parties: enettifee