Our Auth0 setup requires to add connection=123 to the authorize endpoint. I tried several combinations of openid connect authorize parameters without success.
So either please give me a working example or fix the bug - I have the impression that the given parameters are not routed through to the authorize request at all.
Looking at the code it looks like it needs to be in request params.
Try using chrome dev tools, track all HTTP requests, are you certain this allow listed param is in the request params? This is just used to allow list stuff, not to hardcode a value.
If you need to hardcode a value a new feature would need to be built.