feat(unit-links): Reconfigure course outline api call

Re-configuring the api call for the course outline in order to show the vertical pages on the outline page.

lms/djangoapps/course_home_api/outline/serializers.py

@@ -20,7 +20,7 @@ class CourseBlockSerializer(serializers.Serializer):
     def get_blocks(self, block):  # pylint: disable=missing-function-docstring
         block_key = block['id']
         block_type = block['type']
-        children = block.get('children', []) if block_type != 'sequential' else []  # Don't descend past sequential
+        children = block.get('children', []) if block_type != 'vertical' else []  # Don't descend past vertical
         description = block.get('format')
         display_name = block['display_name']
         enable_links = self.context.get('enable_links')