Fixes: #8879
To work around the problem with `$share/` subscriptions the `Mqttv5PahoMessageDrivenChannelAdapter` must provide a `subscriptionIdentifier` into `MqttProperties` on `subscribe()`
* Introduce a `Mqttv5PahoMessageDrivenChannelAdapter.subscriptionIdentifierCounter` according to the MQTT specification:
> 3.8.2.1.2 Subscription Identifier: [..]The Subscription Identifier is associated with any subscription created or modified as the result of this SUBSCRIBE packet. If there is a Subscription Identifier, it is stored with the subscription.
This one is associated with the MQTT session for the current subscriber and does not interfere into other sessions even if identifier is same from the counter.
It works because the Subscription identifier is per session and because you cannot have multiple connection with the same client ID.
**Cherry-pick to `6.2.x` & `6.1.x`**
# Conflicts:
# spring-integration-mqtt/src/main/java/org/springframework/integration/mqtt/inbound/Mqttv5PahoMessageDrivenChannelAdapter.java
57529cc389