Search waiting marketing automation record activities using record ID

There is no custom search_rec_name for record, so all the records are valid.

Closes #13787
(grafted from 8c3bfd7cbc85a01cad95a03fd3537f69f525bcfa)

--HG--
branch : 6.0

modules/marketing_automation/marketing_automation.py

@@ -845,7 +845,7 @@ class RecordActivity(Workflow, ModelSQL, ModelView):
     def _on_event(self, event):
         cls = self.__class__
         record_activities = cls.search([
-                ('record', '=', str(self.record)),
+                ('record', '=', self.record),
                 ('activity', 'in', [
                         c.id for c in self.activity.children
                         if c.event == event and not c.negative]),