With the new admin UI, only change forms based on ModelAdmin ended up

having special widgets (like SelectFilter) set up. The form media

wasn't being referenced (since we were assuming it'd be passed to the

form as the media variable, which isn't true on normal forms) and we

weren't initializing them properly anyway.
We now check for both media and form.media, covering both cases, and

we initialize these widgets in RB.FormView. The latter also now houses

the logic for re-initializing these widgets, moving the functionality

out of RB.Admin.InlineFormGroupView and simplifying form management.

Tested various form pages with these widgets, making sure they worked

as expected.