Issue #3495881 by godotislate, bkosborne, catch, kushagra.goyal: Firefox...

Issue #3495881 by godotislate, bkosborne, catch, kushagra.goyal: Firefox retains form_build_id on form reloads, causing old form cache entry to be used and creating weird behavior for the Media Library widget

(cherry picked from commit f5a836d5)