Support external identities

Supporting external identities would improve the 'users outside your organization' use case

https://learn.microsoft.com/en-us/azure/virtual-desktop/remote-app-streaming/architecture-recs#deploying-azure-virtual-desktop-for-users-outside-your-organization

Users outside the organization will already have their own identity, either in their own AAD (Entra) tenant or with another provider.

Azure Virtual Desktop should support external identities because:

as an application developer, managing their identity is not something that adds unique value;

as the end user, I don't want to remember another password.