Property migration dialogue doesn't broadcast 500 errors

[joelvdavies]

While testing the write conflict message (see #1121), I noticed that if a 500 is returned, the only thing that is shown is:

but nothing happens and no error is displayed.

[joshuadkitenge]

What did you do to the API to trigger this error? It should be working as the handleTransferState in the onError should catch all errors . However looking at the code the types might not be correct for a 500 error

[joelvdavies]

It was on ral-facilities/inventory-management-system-api#433 before I actually caught the error to raise it as a 409, so it was a 500 with the same message. I put an OperationFailure on this line https://github.com/ral-facilities/inventory-management-system-api/blob/9922030645750d2bf7aca34cd42e600c8a7b8140/inventory_management_system_api/services/catalogue_category_property.py#L109