AttributeError when updating an existing Reference metadata

Sentry Issue: ARKINDEX-BACKEND-T7

AttributeError: 'MetaDataUpdateSerializer' object has no attribute 'reindex_element'
(10 additional frame(s) were not displayed)
...
  File "rest_framework/mixins.py", line 82, in partial_update
    return self.update(request, *args, **kwargs)
  File "rest_framework/mixins.py", line 68, in update
    self.perform_update(serializer)
  File "rest_framework/mixins.py", line 78, in perform_update
    serializer.save()
  File "rest_framework/serializers.py", line 200, in save
    self.instance = self.update(self.instance, validated_data)
  File "arkindex/documents/serializers/light.py", line 163, in update