[CIAM CUD] .NET daemon sample updated for CUD

[bgavrilMS]

See https://github.com/Azure-Samples/ms-identity-ciam-dotnet-tutorial for existing samples.

The goal is to update all confidential client samples (web app, web api, daemon) with details on how to use CIAM CUD authorities (should be just a paragraph). Samples must be manually tested with CIAM CUD.

This issue is for the daemon app:

https://github.com/Azure-Samples/ms-identity-ciam-dotnet-tutorial/blob/main/2-Authorization/3-call-own-api-dotnet-core-daemon/README.md