Close lightbox when clicking on image-frame

Summary: Ref T3612. Moves the listener to the frame of the image.

Test Plan: Click on image, no close, click on grey frame, closes image. Test image and document, clicking on arrows.

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Maniphest Tasks: T3612

Differential Revision: https://secure.phabricator.com/D16959