Fixes T11785. Lightbox calls JX.Stratcom.pass() to let other handlers react, but should not. At least today, we never put, e.g., links inside a lightbox.
This code appears in the original commit so it was probably just copy/pasted from somewhere and I missed it in review.
(Or there's some edge case I'm not thinking of and we'll figure it out soon enough.)
Additionally, blacklist /file/data/ from Quicksand naviagtion: Quicksand should never fetch these URIs.