Lack of systemuser-support for SO endusercontext/systemlabels

[elsand]

Description

Supplying a invalid EndUserId to v1/serviceowner/dialogs/:dialogId/endusercontext/systemlabels?EndUserId= causes a 400 but without any errors. We must support supplying systemuserid as EndUserId.

Reproduction

1. Perform a SO authenticated request toapi/v1/serviceowner/dialogs/{dialogId}/endusercontext/systemlabels?EndUserId=urn:altinn:systemuser:uuid:{systemUserUuid}

Expected behavior

The label request is processed if given a valid and the supplied end user is authorized. If a invalid (ie. not well-formed) EndUserId, the returned ProblemDetails should indicate this.

Actual behavior

A 400 Bad Request is returned with an ProblemDetails missing errors:

{
  "type": "https://datatracker.ietf.org/doc/html/rfc7231#section-6.5.1",
  "title": "One or more validation errors occurred.",
  "status": 400,
  "instance": "/api/v1/serviceowner/dialogs/0197ee86-a1fd-71c4-9762-5339e51c3e68/endusercontext/systemlabels",
  "traceId": "00-8caf832f3b071a5f6277ba180f948f48-7aeaf9dda0d8271d-01"
}

Additional information

SystemUsers should be allowed in ServiceOwnerOnBehalfOfPersonMiddleware, same as ServiceOwner/Dialogs/Queries/Get/GetDialogQueryValidator.cs. As the middleware always handles validation of EndUserId, the query specific rule should probably be removed.