Revert "make course listsings (front page) opaque keys compliant"

This reverts commit e412f55f.

lms/djangoapps/branding/__init__.py

@@ -29,7 +29,7 @@ def get_visible_courses():
     if filtered_by_org:
         return [course for course in courses if course.location.org == filtered_by_org]
     if filtered_visible_ids:
-        return [course for course in courses if course.id.to_deprecated_string() in filtered_visible_ids]
+        return [course for course in courses if course.id in filtered_visible_ids]
     else:
         # Let's filter out any courses in an "org" that has been declared to be
         # in a Microsite