Fixes "splat" error on New Files

You should now be able to view folders
within files without any errors.

test plan:
* Enable "Better File Browsing" feature flag
* Go to any course's Files page that has folders
  and other uploaded content
* Navigate to a child folder
* You should see the contents of the child folder
  without error

Change-Id: I09359714fc0f49a6e9f5d40fa5ef881fa07052d4
Reviewed-on: https://gerrit.instructure.com/43120
Reviewed-by: Clay Diffrient <cdiffrient@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
Product-Review: Dan Minkevitch <dan@instructure.com>
QA-Review: Dan Minkevitch <dan@instructure.com>