Fix appservice EDUs failing to send if the EDU doesn't have a room ID (#13236)

* Fix appservice EDUs failing to send if the EDU doesn't have a room ID

As is in the case of presence.

* changelog

* linter

* fix linter again

changelog.d/13236.bugfix

@@ -0,0 +1 @@
+Fix appservices not receiving room-less EDUs, like presence, if enabled.

synapse/appservice/scheduler.py

@@ -319,7 +319,9 @@ class _ServiceQueuer:
         rooms_of_interesting_users.update(event.room_id for event in events)
         # EDUs
         rooms_of_interesting_users.update(
-            ephemeral["room_id"] for ephemeral in ephemerals
+            ephemeral["room_id"]
+            for ephemeral in ephemerals
+            if ephemeral.get("room_id") is not None
         )
 
         # Look up the AS users in those rooms