workflow: remove aggregation email if can not send it (#19389)

wcs/wf/aggregation_email.py

@@ -92,12 +92,15 @@ def send_aggregation_emails(publisher):
 
     cache = {}
     for aggregate_id in AggregationEmail.keys():
-        role = Role.get(aggregate_id)
-        if not role.emails:
-            continue
-
         aggregate = AggregationEmail.get(aggregate_id)
         aggregate.remove_self()
+
+        try:
+            role = Role.get(aggregate_id)
+        except KeyError:
+            continue
+        if not role.emails:
+            continue
         if not aggregate.items:
             continue