Backlight Jumps to 100% if set to 0.
When setting the backlight to any value 1-100% it works as expected. However when the backlight is set to 0. Apple H
ome thinks that it is actually 100%. From the logs everything looks normal. No improper value is sent from or to the tv. The payload has backlight to the values you'd expect. From digging into the code I have a guess. The `LightbulbService` has 2 `Characteristics` `On` & `Brightness`. I think that when Brightness is 0. It feels that the Characteristic of `On` should take priority. Which would put the light bulb at 100%. If that is the case. Perhaps we change the `On Characteristic` to also take into account the value of the backlight. `Tv.isON && Tv.Backlight !== 0` etc

![Showcase](https://github.com/merdok/homebridge-webos-tv/assets/4674003/bc2cfc08-2e89-499f-8ca1-6fabe0cf47ac)
