Music sensor - add more properties

[juan518munoz]

As visible on the embedded music player on ZeppOS, the song duration and current progress is accessible to the watch, but not on the current sensor API. It would be handy if length and playbackPosition are added.

https://docs.zepp.com/docs/reference/device-app-api/hmSensor/sensorId/MUSIC/#creating-sensors

[htoooth]

hi @juan518munoz:
Thank you for your feedback. We will add this feature to our version plan.