Shared subscription not working correctly

- [x] Bug exists Release Version 1.2.5 ( Master Branch)
- [ ] Bug exists in MQTTv3 Client on Snapshot Version 1.2.6-SNAPSHOT (Develop Branch)
- [ ] Bug exists in MQTTv5 Client on Snapshot Version 1.2.6-SNAPSHOT (Develop Branch)

When receiving a message on a [shared subscription](https://docs.oasis-open.org/mqtt/mqtt/v5.0/os/mqtt-v5.0-os.html#_Toc3901250) the registered `IMqttMessageListener.messageArrived(` isn't called. Instead the registered `MqttCallback.messageArrived(` is called. Workaround could be to subscribe as shared and non-shared subscription.

Reproduce:
1. subscribe to topic `$share/group1/any/topic`
2. send message to to topic `any/topic`

Start by reproducing the issue with the shared subscription `$share/group1/any/topic` and a message sent to `any/topic` in the Java MQTT client. Trace how messages are dispatched between `IMqttMessageListener.messageArrived` and `MqttCallback.messageArrived`; done means shared-subscription messages invoke the registered listener as expected, with regression coverage for the reported reproduction.

Written by the indexing model from the issue text.