slapos_accounting: Skip Validation if instance is owned by a super user

This cause a lot of headeache during the tests.

master/bt5/slapos_accounting/SkinTemplateItem/portal_skins/slapos_contract/SoftwareInstance_requestValidationPayment.py

@@ -5,7 +5,11 @@ if REQUEST is not None:
 portal = context.getPortalObject()
 software_instance = context
 hosting_subscription = software_instance.getSpecialiseValue()
+if hosting_subscription is None:
+  return
 person = hosting_subscription.getDestinationSectionValue(portal_type='Person')
+if person is None:
+  return
 payment_portal_type = "Payment Transaction"
 contract_portal_type = "Cloud Contract"