I was interested in the question myself, and I've just watched Netflix on a vanilla build (no additional configurations / network restrictions) AVD client. There are no Microsoft enforced Network restrictions when accessing your own VM's inbound or outbound, only those imposed by your organisation.
There are some multimedia restrictions with multi media redirection, which does directly call out Netflix because it is protected content https://learn.microsoft.com/en-us/azure/virtual-desktop/troubleshoot-multimedia-redirection. kind regards Alistair