Hidden Inputs should not (automatically) be localized

(We're approaching the limit of our approach of automatically localizing everything)

Since 893d8de6f5 Django implements localization on hidden inputs. However, this
messes our defaults up seriously: hidden inputs are very often an FK that is evaluated
using a ChoiceField in the next screen.

Since we never use the localize=True property of hidden widgets, we undo is_localized
in those cases.