slapos_wechat: No need to check if invoice exists

On certain cases, the invoice is created later on by activies.

master/bt5/slapos_wechat/SkinTemplateItem/portal_skins/slapos_wechat/Base_queryWechatOrderStatusByTradeNo.py

@@ -12,10 +12,7 @@ payment = portal.accounting_module[trade_no]
 
 if person is None:
   if portal.portal_membership.isAnonymousUser():
-    invoice = payment.getCausalityValue()
-    if invoice is not None and invoice.getCausalityRelated(portal_type="Subscription Request"):
-      person = payment.getDestinationSectionValue()
-
+    person = payment.getDestinationSectionValue()
 
 return person.Person_restrictMethodAsShadowUser(
   shadow_document=person,