Compatibility with CircuitPython

[llamafilm]

This is a no-op for anyone using pack_advertisement.

I could not find any way to use that function with adafruit_ble in CircuitPython, so I made pack_service_data public and changed its format for compatibility. That library has its own class to create Advertisements, which adds the AD type, length, and name.

Example usage:

fromadafruit_bleimportBLERadiofromadafruit_ble.advertisingimportAdvertisementfrombthomeimportBTHomebeacon=BTHome(debug=True)
beacon.temperature=25bthome_service_data=beacon.pack_service_data(BTHome.TEMPERATURE_SINT16_X100)
bthome_advert=Advertisement()
bthome_advert.data_dict[0x16] =bthome_service_datable=BLERadio()
ble.name="Feather Sense"ble.start_advertising(bthome_advert)