Fixes #11904 TypeFeatureProvider throws if a Razor Page has no PageModel

[jtkech]

Fixes #11904

We now can use the [Feature()] attribute on a razor PageModel if it is a component, meaning a non abstract public class, e.g. not an internal class when defined in a razor page itself, and we use the ITypeFeatureProvider to retrieve the feature related to a given PageModel.

The problem is that when no PageModel is defined for a razor page, e.g. only @functions handlers, the related page ModelType is then of type Object which is non abstract and public, so considered as a component.

In that case ITypeFeatureProvider.GetFeatureForDependency(pageModelType) throw an exception.

A quick solution was to change the following by also checking the Object type.

    private bool IsComponentType(Type type)
    {
        return type.IsClass && !type.IsAbstract && type.IsPublic &&
            type != typeof(Object); <= The change
    }

But I think it is better and simpler to just check if the page ModelType has a custom attribute of type FeatureAttribute, and if so just use it to retrieve the related feature.

@ns8482e if you can take a look ;)

[ns8482e]

Nice - Can you add sample feature in OrchardCore.Demo?

[jtkech]

@ns8482e Okay will do

[ns8482e]

LGTM

[jtkech]

@ns8482e Okay, done and tried ;)