[Bug] Shelly 1 which is offline according to admin page can still be turned on but not off
**Describe the bug**
The plugin indicates that a Shelly 1 is offline but the device can still be turned on via Homebridge. Once turned on it can not be turned off anymore.

**Environment:**
 - Shelly device(s): Shelly 1
 - Plugin version: 0.16.0
 - Device running homebridge: Raspberry Pi Zero W