erp5_catalog: Change the context for the python script to get Method list from catalog objects

bt5/erp5_catalog_transition/SkinTemplateItem/portal_skins/erp5_core/Catalog_getMethodList.py

-method_list = context.getPortalObject().portal_catalog.getSQLCatalog().Catalog_getCatalogMethodIds()
+# This script should always be called with context as either
+# ERP5Catalog object or SQLCatalog.Catalog object
+
+method_list = context.Catalog_getCatalogMethodIds()
 
 method_list = [method[0] for method in method_list]
 return method_list