feat: communicate face to CB

Had to do some weird socket stuff

ref: N25B-397

src/robot_interface/endpoints/main_receiver.py

@@ -74,7 +74,12 @@ class MainReceiver(ReceiverBase):
         :return: A response dictionary with endpoint descriptions as data.
         :rtype: dict[str, list[dict]]
         """
-        endpoints = [socket.endpoint_description() for socket in state.sockets]
+        endpoints = [
+            socket.endpoint_description()
+            for socket in state.sockets
+            if socket.endpoint_description() is not None
+        ]
+
 
         return {"endpoint": "negotiate/ports", "data": endpoints}