Makes new file preview film strip links work

fixes CNVS-16240

Test Plan
  - Enable New Files
  - Preview a folder with multiple files
  - Open up the footer
  - Click on another item in the footer
  - The preview should change to that file.

Change-Id: I144b00a01fb8dfee625a66b49b71a71a03677c8e
Reviewed-on: https://gerrit.instructure.com/43273
Reviewed-by: Dan Minkevitch <dan@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
QA-Review: Dan Minkevitch <dan@instructure.com>
Product-Review: Dan Minkevitch <dan@instructure.com>