datacite: update URLs and metadata of remaining Schema 3 records

[GraemeWatt]

Looking at DataCite Fabrica for the CERN.HEPDATA account, there are a total of 135,890 DOIs with state "Findable", of which 135,240 have Schema 4 metadata, but 623 still have Schema 3 metadata (this sums to 135,863 leaving a difference of 27?):

https://doi.datacite.org/repositories/cern.hepdata/dois?schema-version=3&state=findable

I've tried to run CLI commands to update these DOIs, but it doesn't seem to work, although I don't see any errors on Sentry or Flower. It needs further investigation why these 623 DOIs with Schema 3 metadata cannot be updated.