Fixes:
- No more
error from callback ... 'deviceSn'log spam frompybluetti.websocket(#35). The cloud's notification topic also carries messages that are not device notifications, and the handler raised on every one of them - up to several hundred error lines a day on some accounts. They are now skipped at debug level; real device pushes and the 30-second polling fallback are unaffected, as they already were.