trade: disable predicate features for Delivery Cells

Especially because we do not need them in predicate table.
This applies to many cell portal types.

bt5/erp5_trade/SkinTemplateItem/portal_skins/erp5_trade/DeliveryCell_asPredicate.py

-return context.generatePredicate(
-                   multimembership_criterion_base_category_list=('industrial_phase',))
+"""We do not need use delivery cells as predicates.
+"""
+return None