http 401 on added reference sends input into nothingness

[WillemElbers]

Two issues happening:

1. Validation on UI is passing allowing to save the collection.
2. Validation in backend is failing because of 401, preventing the collection from being saved, but this is not propagated to the UI and the input is lost.

Stacktrace:

2024-05-16 15:06:18,954 WARN [org.apache.wicket.markup.resolver.AutoLinkResolver#newAutoComponent:462] - Did not find corresponding java class: eu.clarin.cmdi.virtualcollectionregistry.gui.pages.submission.AboutPage
2024-05-16 15:08:00,715 INFO [eu.clarin.cmdi.virtualcollectionregistry.gui.pages.crud.v2.editor.editors.authors.AuthorsEditor#populateItem:445] - Authors ListView: Van Uytvanck, Dieter, id=null, display order=0
2024-05-16 15:09:21,241 DEBUG [eu.clarin.cmdi.virtualcollectionregistry.gui.pages.crud.v2.editor.editors.references.ReferencesEditor#completeSubmit:472] - Completing reference submit: value=https://drive.google.com/file/d/1Fe4jhKpK1xrv6sZzLdkGpIZXEGb2L4Ih/view,title=Flyer PDF: A PID is forever
2024-05-16 15:09:21,242 INFO [eu.clarin.cmdi.virtualcollectionregistry.gui.pages.crud.v2.editor.editors.authors.AuthorsEditor#populateItem:445] - Authors ListView: Van Uytvanck, Dieter, id=null, display order=0
2024-05-16 15:10:10,821 INFO [eu.clarin.cmdi.virtualcollectionregistry.gui.pages.crud.v2.editor.editors.authors.AuthorsEditor#populateItem:445] - Authors ListView: Van Uytvanck, Dieter, id=null, display order=0
2024-05-16 15:10:12,551 DEBUG [eu.clarin.cmdi.virtualcollectionregistry.VirtualCollectionRegistryImpl#createVirtualCollection:149] - creating virtual collection
2024-05-16 15:10:12,968 INFO [eu.clarin.cmdi.virtualcollectionregistry.VirtualCollectionRegistryImpl#createVirtualCollection:154] - Validation failed:
2024-05-16 15:10:12,969 INFO [eu.clarin.cmdi.virtualcollectionregistry.VirtualCollectionRegistryImpl#createVirtualCollection:156] -    validation error: https://drive.google.com/file/d/1Fe4jhKpK1xrv6sZzLdkGpIZXEGb2L4Ih/view: 'https://drive.google.com/file/d/1Fe4jhKpK1xrv6sZzLdkGpIZXEGb2L4Ih/view' received invalid HTTP response: HTTP 401 Unauthorized