[Feature Request]: Configuration for discovery endpoint custom query parameters.

[mdcarr941]

Is your feature request related to a problem? Please describe.
When adding custom claims to JWT tokens in Microsoft Entra ID, you must configure a custom signing key (or disable claims validation, but that is definitely not a good idea). In order to get the corresponding public key for verification, the Open ID connect client is required to send the appid parameter as a query parameter with the discovery request [1]. There doesn't seem to be a way of to do this with angular-auth-oidc-client as of today.

Describe the solution you'd like
A new configuration parameter, modeled after customParamsAuthRequest, called customParamsDiscoveryRequest which has type object. The keys in this object are the verbatim names of the query parameters to add to the discovery request and the corresponding values define what to send in that parameter.

Describe alternatives you've considered
I'm considering moving to the MSAL for frontend authentication.