Make the PusherSlaveStore inherit from the slave RoomStore

So that it has access to the get_retention_policy_for_room function which is required by filter_events_for_client.

synapse/app/pusher.py

@@ -33,6 +33,7 @@ from synapse.replication.slave.storage.account_data import SlavedAccountDataStor
 from synapse.replication.slave.storage.events import SlavedEventStore
 from synapse.replication.slave.storage.pushers import SlavedPusherStore
 from synapse.replication.slave.storage.receipts import SlavedReceiptsStore
+from synapse.replication.slave.storage.room import RoomStore
 from synapse.replication.tcp.client import ReplicationClientHandler
 from synapse.server import HomeServer
 from synapse.storage import DataStore
@@ -45,7 +46,11 @@ logger = logging.getLogger("synapse.app.pusher")
 
 
 class PusherSlaveStore(
-    SlavedEventStore, SlavedPusherStore, SlavedReceiptsStore, SlavedAccountDataStore
+    SlavedEventStore,
+    SlavedPusherStore,
+    SlavedReceiptsStore,
+    SlavedAccountDataStore,
+    RoomStore,
 ):
     update_pusher_last_stream_ordering_and_success = __func__(
         DataStore.update_pusher_last_stream_ordering_and_success