erp5_pdm: respect existing predicate in TransformationOptionalResource_asPredicate.

bt5/erp5_pdm/SkinTemplateItem/portal_skins/erp5_pdm/TransformationOptionalResource_asPredicate.py

-option_category = context.getOptionList()
-option_base_category = []
-if len(option_category) > 0:
-  option_base_category = [option_category[0].split('/')[0]]
+membership_criterion_category_list = context.getMembershipCriterionCategoryList()
+membership_criterion_base_category_list = context.getMembershipCriterionBaseCategoryList()
+
+for option in context.getOptionList():
+  membership_criterion_category_list.append(option)
+  membership_criterion_base_category_list.append(option.split('/')[0])
 
 new_context = context.asContext(
-    membership_criterion_category=option_category,
-    membership_criterion_base_category=option_base_category)
+    membership_criterion_category=tuple(set(membership_criterion_category_list)),
+    membership_criterion_base_category=tuple(set(membership_criterion_base_category_list)))
 return new_context