Renders the Taxon UI even if the "Any Types" filter is selected

If you have an interface that extends Taxon, and more than 1 class that implements it, and then add the interface as a field on a type like so:

public class Tag extends Taxon { }
public class TagType1 implements Tag { }
public class TagType2 implements Tag { }

public class Article extends Content {
    private List<Tag> tags;
}

Previously, when adding the "tags" in the CMS the Taxon UI would not display while the "Any Types" search filter was selected. This pull request fixes that issue.