Confirming study through Dataporten should have better error-handling

[henrikhorluck]

As it stands right now, errors on the side of Dataporten propagates to our server, causing a 500-error, examples would be:

• https://sentry.io/organizations/dotkom/issues/1143315937/?environment=PRODUCTION&project=204971&query=is%3Aunresolved&statsPeriod=14d
• https://sentry.io/organizations/dotkom/issues/1133738025/?project=204971&query=is%3Aunresolved
  Note: you need to be in dotkom to read the sentry messages due to personal information.

This is likely an issue related to the account not being registred in fully / correct at Dataporten/Feide, and should give more meaningful error-messages than "Null"

[oleast]

Fixed in part by #2290