Using API to get a data element that doesn't exist responds with 500 instead of 404

[MagnusNordboe]

Description of the bug

If I have a valid user logged in, that has created an instance with a valid instanceId, and I ask for an not existing but valid data id on the data/{dataGuid} GET endpoint, the server responds with 500 internal server error.

Expected behavior: The server should respond with a 404 not found, as I'm asking for an element that doesn't exist. Potentially a 403 bad request. This works properly if the request is not a properly formatted guid, but with proper guid formatting the server assumes it made a mistake.

Steps To Reproduce

1. Authenticate as a test user with access to vpfo : user_id: 160616; party_id: 51882621
2. Create instance: POST https://brg.apps.tt02.altinn.no/brg/aarsregnskap-vpfo-202405/instances?instanceOwnerPartyId=51882621
3. Get data element with a valid Guid that does not exist: GET https://brg.apps.tt02.altinn.no/brg/aarsregnskap-vpfo-202405/instances/51882621/{{schema_instance_id}}/data/82a351d9-807f-4949-9d6b-3cc7eea38a17
4. The server will respond with 500

Additional Information

The bug is not exclusive to VPFO, and should be reproduceable with any app / data element