Authorization scheme should raise an exception when the user_id is not in the JWT payload

[joeribekker]

The JWT payload attribute user_id is mandatory, see also: https://github.com/VNG-Realisatie/gemma-zaken/blob/master/docs/_content/standaard/standaard.md#autorisatie

vng-api-common/vng_api_common/middleware.py

Line 50 in 4b1ac2b

def payload(self) -> dict:

[annashamray]

According to this doc user_id can be absent:
"Indien deze claim niet aanwezig is, wordt de X-NLX-Request-User-Id uitgelezen."

[joeribekker]

Good observation! We need to resolve this documentation conflict.

[sergei-maertens]

This is a breaking change - also because we need to update the API spec w/r to the NLX headers (that aren't supported after all)