Fixes: #9276
The current Eclipse Paho client has wrong removal from map logic which leads to the
`ConcurrentModificationException` when we unsubscribe from topic.
* Catch a `ConcurrentModificationException` `this.mqttClient.unsubscribe()` and just log it as an `error`
(cherry picked from commit 12fc353db1)
# Conflicts:
# spring-integration-mqtt/src/main/java/org/springframework/integration/mqtt/inbound/Mqttv5PahoMessageDrivenChannelAdapter.java