V13: Set request culture for VirtualPageController

[nikolajlauridsen]

Fixes #16555.

Following #16218 VirtualPageController requests no longer hit the UmbracoRouteValueTransformer. This had the side effect that the request culture was no longer properly set in the VariationContext and PublishedRequest.

To fix this I've:

• Split FindDomain into FindDomain and FindAndSetDomain
• This allowed me to create two new methods: RouteDomain and UpdateVariationContext
• Call UpdateVariationContext before FindContent is invoked, ensuring that the variation context is correctly configured for finding the content
• Call FindDomain to ensure the PublishedRequest and VariationContext have the correct cultures configured.

Testing

Configure a virtual page controller like in the issue, and ensure that the culture specified in the domains is set correctly. You can check it like so:

IVariationContextAccessor variationContextAccessor =
        context.HttpContext.RequestServices.GetRequiredService<IVariationContextAccessor>();
var culture = variationContextAccessor.VariationContext?.Culture;

[Zeegaan]

Looks good, tests good 🚀