documentation: openseadragon does not display Paged Content

openseadragon does not display Paged Content.

Claw-playbook version: 1d1ffc2f1ff8f712992916320dc2196fc930dfb9

Steps to reproduce

• Create a Repository Item with model Paged Content
• Add a Child with model Page
• Add a media to that child (File - Tiff) with Media Use being Original
• Go to the Paged Content node

Expected

• The content is shown in the openseadragon viewer

Actual

• The viewer is shown, but there is a 500 error

AJAX request returned 500: http://127.0.0.1:8080/cantaloupe/iiif/2/http%3A%2F%2Flocalhost%3A8000%2Fsites%2Fdefault%2Ffiles%2F2019-10%2F2-Service%2520File.jpg