Ignore notification counts from rooms you've left

This fixes a bug in #16904,
where notifications the user had received from rooms they had left were
still being counted.

This was most apparent for rejected invites, where you "leave" the room
you were invited to without sending a read receipt in that room, thus
clearing the notification.

synapse/storage/databases/main/event_push_actions.py

@@ -404,7 +404,11 @@ def _get_unread_counts_by_room_for_user_txn(
                 SELECT e.room_id, notif_count, e.stream_ordering, e.thread_id, last_receipt_stream_ordering,
                     ev.stream_ordering AS receipt_stream_ordering
                 FROM event_push_summary AS e
-                INNER JOIN local_current_membership USING (user_id, room_id)
+                INNER JOIN local_current_membership as lcm ON (
+                    e.user_id = r.user_id
+                    AND e.room_id = r.room_id
+                    AND lcm.membership = 'join'
+                )
                 LEFT JOIN receipts_linearized AS r ON (
                     e.user_id = r.user_id
                     AND e.room_id = r.room_id
@@ -472,7 +476,11 @@ def _get_unread_counts_by_room_for_user_txn(
                 SELECT e.room_id, e.stream_ordering, e.thread_id,
                     ev.stream_ordering AS receipt_stream_ordering
                 FROM event_push_actions AS e
-                INNER JOIN local_current_membership USING (user_id, room_id)
+                INNER JOIN local_current_membership as lcm ON (
+                    e.user_id = lcm.user_id
+                    AND e.room_id = lcm.room_id
+                    AND lcm.membership = 'join'
+                )
                 LEFT JOIN receipts_linearized AS r ON (
                     e.user_id = r.user_id
                     AND e.room_id = r.room_id
@@ -514,7 +522,11 @@ def _get_unread_counts_by_room_for_user_txn(
                     SELECT e.room_id, e.stream_ordering, e.thread_id,
                         ev.stream_ordering AS receipt_stream_ordering
                     FROM event_push_actions AS e
-                    INNER JOIN local_current_membership USING (user_id, room_id)
+                    INNER JOIN local_current_membership ON (
+                        e.user_id = r.user_id
+                        AND e.room_id = r.room_id
+                        AND lcm.membership = 'join'
+                    )
                     LEFT JOIN receipts_linearized AS r ON (
                         e.user_id = r.user_id
                         AND e.room_id = r.room_id