Visibility SortClause ignores Content Visibility setting.

Steps to reproduce:
1. Login as admin
2. Go to Content -> Content Structure
2. Create a new Folder named "TestContentVisibility"
3. Hide the Content (not Location!)
4. Search for it using Visibility SortClause:

        $query = new LocationQuery();
        $query->sortClauses = [new SortClause\Location\Visibility(Query::SORT_DESC)]

Expected:
The Location of the Content Item we've hidden is at the top

Actual:
The Location of the hidden Content Item is not at the top of the results.