This endpoint is used to complete the OIDC process where the server exchanges the authCode for an ID token.
The OIDC provider redirects to this endpoint (/irs/oidc/v1/flows/callback),
which retrieves the token data and provides it for the flow in the context of which the communication
process with the provider was initiated.
Afterwards, this endpoint performs a redirect to one of the client-selected URLs that were previously
selected during the consentUrl request.
A url query parameter "flowId" is added to the redirect, which can be used to get a
response from the flow (see /self-service/v1/responses/flows/{id})