fix(home-assistant): fix MQTT options

A recent change in the library started modifying the options object
directly, which doesn't play well with the immutable config options we
passed in until now.

Closes #321

src/integrations/home-assistant/home-assistant.service.ts

@@ -65,7 +65,7 @@ export class HomeAssistantService
     try {
       this.mqttClient = await mqtt.connectAsync(
         this.config.mqttUrl,
-        this.config.mqttOptions,
+        { ...this.config.mqttOptions },
         false
       );
       this.mqttClient.on('message', this.handleIncomingMessage.bind(this));