portal: fix clean-rooms

Signed-off-by: Sumner Evans <sumner@beeper.com>

mautrix_instagram/portal.py

@@ -203,6 +203,7 @@ class Portal(DBPortal, BasePortal):
 
     @classmethod
     def init_cls(cls, bridge: "InstagramBridge") -> None:
+        BasePortal.bridge = bridge
         cls.config = bridge.config
         cls.matrix = bridge.matrix
         cls.az = bridge.az