membershipworks: Only send event survey emails to non-voided participants

membershipworks/tasks/event_survey_emails.py

@@ -23,7 +23,15 @@ class EventSurveyEmail(TemplatedMultipartEmail):
 
     @classmethod
     def render_for_event(cls, event: EventExt) -> Iterable[mail.EmailMessage]:
-        for name, email in event.attendees.values_list("name", "email"):
+        # not using event.attendees because that makes getting ticket count harder
+        for attendee in event.details["usr"]:
+            # skip users with no tickets, as they were Voided
+            if sum(attendee["tkt"]) == 0:
+                continue
+
+            name = attendee["nam"]
+            email = attendee["eml"]
+
             sanitized_email = mail.message.sanitize_address(
                 (name, email), settings.DEFAULT_CHARSET
             )