Support WebSocketChannel2023 for the Solid Notifications Aggregator.

[argahsuknesib]

Currently, the websocketchannel2023 is not supported as the underlying solid server used (CSS) doesn't support multithreading for websocket notifications which therefore hinders scalability.
The recent most solid notifications protocol is not supported by any other implementations of the solid server too.

Relevant Issue : CommunitySolidServer/CommunitySolidServer#1809

[argahsuknesib]

If you wish to implement the websocketchannel2023, please feel free to create a PR. Thanks!