Update Blazor Identtiy scaffolder to use built-in AuthenticationStateProviders once available

[danroth27]

In .NET 9 we plan to make the AuthenticationStateProviders used to enable authentication in the Blazor Web App template built-in to the framework. Once that is done we expect to update the template code to use them and we should make the same changes in the Blazor Identity scaffolder.

The framework change is tracked by dotnet/aspnetcore#52769.

@halter73 @JeremyLikness @deepchoudhery