Before this commit, an optional consent that was not answered was posted
with the choice value set to null. This was rejected by the backend,
making it impossible to not answer an optional consent. It is now
possible.

Resolves: GREG-187

If we don't fetch the info again, the frontpage will redirect us back to
/guestregister because the user does not have
registration_completed_date set.

- Passport Country now displays two letter code after
   selection.
- A heading has been added for identity information.
- An error message is now displayed if the user inputs both national id
   and passport information.

Resolves: GREG-120