Intermittent: Error cancelling request ("Cannot edit closed request")

CB: Matt Reno figured out how to repro this - YAY!

Steps to repro:

1. Create a request
2. From the pane header dropdown, select Cancel request
3. Click the cancel button a second or third time while waiting for the popup to close

Actual: Error generated

Expected: One way to address this would be to disable the cancel button after clicked and show a loading indicator while it does the actual cancellation

Additional info: After clicking OK, the request is, indeed, cancelled

-------- OLD DETAILS PROBABLY NO LONGER RELEVANT ----------------

Screenshot of request, in case that's useful:

2019-09-13 CB: I saw this again today in folio-snapshot while cancelling this record. It was the one and only request in the system. The error pops up but when you click it away, the request is indeed cancelled.

2019-09-20 CB: mwalter saw this today during BugFest testing and recorded this: https://youtu.be/4UgBmbTLV6I

2019-10-25 Reproduced this again today between 11:40 and 11:46 am CET. We have logs for the day (attached) which we can investigage marcjohnson says the error is definitely coming from the backend and, it looks like the UI may be doing something twice or in two parts.

• Record seen today: https://folio-snapshot.aws.indexdata.com/requests/view/f2141755-b654-4593-8e91-5c6abbefa453?query=4539876054383
• Screenshot of error:
• Screenshot of developer tools: