Only resources that can be copied should be listed in the import learning resources function in the question pool, not the referenceable ones

in the question pool, when trying to import a test or questionnaire, only your own resources and those marked as referenceable by other authors are listed to import. This is not quite correct though - an author marking a resource as referenceable doesn't necessarily allow for a test or questionnaire to be copied and manipulated. but importing such a resource does just that, it allows another author to import test items as his own, for him to edit and manipulate.
Therefore, only those resources that are marked "Can be copied" should be listed for import in the question pool