IsValidOnlineHost missing valid sovereign cloud host addresses

[whobday]

https://github.com/microsoft/PowerPlatform-DataverseServiceClient/blob/03fa4d1132c90af9f6c08e581119e7407ca61fa7/src/GeneralTools/DataverseClient/Client/Utils/Utils.cs#L259

It's not possible to connect to sovereign clouds not listed above using a connection string and the dvsc. I've verified that I can create a connection if I bypass using connection strings.

Ideally, there would be a means for expanding the list of valid online endpoints, rather than explicitly including the specific clouds.