Resource definition filter callback for primary resource is not called on secondary endpoint

[bart-degreed]

Primary use case is support for soft deletes.

For example, assume resources Blog and Article have an IsDeleted json:api attribute and their resource definitions override OnApplyFilter, which returns "equals(IsDeleted,'false')", or ANDs that with any existing incoming filter.

The bug is that for /blogs/1/articles, BlogResourceContext.OnApplyFilter is not called. So if blog 1 was soft-deleted, this incorrectly returns its articles.

The same problem applies to .../relationships/... requests.