Fixes https://github.com/spring-projects/spring-integration/issues/8550 Turns out the Paho MQTT client does not re-subscribe when connection re-established on automatic reconnection * Fix `Mqttv5PahoMessageDrivenChannelAdapter` to always subscribe to its topics in the `connectComplete()` independently of the `reconnect` status * Verify behavior with `MOSQUITTO_CONTAINER` image restart in Docker