MQTT Interface topic not updating to "Offline' state
**System**
Paradox MG5050 v4.133
IP150 firmware 1.39
Using Dev branch

**Describe the bug**
The state/value in the 'paradox/interface/MQTTInterface' topic does not change to 'offline' when you disconnect/stop the pai script. I also tested this by entering in the wrong user/pass MQTT credentials in the pai.conf thus causing the script to not connect MQTT on startup. In each case the state is always "Online". The topic does seem to update the "Online" state though without issue.

**To Reproduce**
Steps to reproduce the behavior (2 methods):
METHOD 1:
1. Start script
2. Control C to disconnect/stop the script
3. View the 'paradox/interface/MQTTInterface' topic value in MQTT client

METHOD 2:
1. Modify MQTT username or password credentials in pai.conf so that they are incorrect
2. Start script
3. View the 'paradox/interface/MQTTInterface' topic value in MQTT client

