Don't insert without deduplication. In this case we never actually use this...

Don't insert without deduplication. In this case we never actually use this table, so simply remove the insert entirely

synapse/storage/events.py

@@ -127,28 +127,6 @@ class EventsStore(SQLBaseStore):
                 ],
             )
 
-        if event.is_state() and is_new_state:
-            if not backfilled and not context.rejected:
-                self._simple_insert_txn(
-                    txn,
-                    table="state_forward_extremities",
-                    values={
-                        "event_id": event.event_id,
-                        "room_id": event.room_id,
-                        "type": event.type,
-                        "state_key": event.state_key,
-                    },
-                )
-
-                for prev_state_id, _ in event.prev_state:
-                    self._simple_delete_txn(
-                        txn,
-                        table="state_forward_extremities",
-                        keyvalues={
-                            "event_id": prev_state_id,
-                        }
-                    )
-
         outlier = event.internal_metadata.is_outlier()
 
         if not outlier: