Revert "Exit Lightbox when clicked on backdrop"

This reverts commit 4280dd8b83eab0a21b0e38387289274777588c5f.

After product discussion, we decided this was a bad idea. Sorry, Tony.

Change-Id: Ib59d75132c2a301f83d080b0f963e2a9d8b9b277
Merge "Revert "Exit Lightbox when clicked on backdrop""