Show serial number rather than uniqueID on dbus.
Show serial number rather than uniqueID on dbus.

This is made so that for old PV-inverters that don't support
getInverterInfo.cgi, and also not SunSpec, it will still show
the uniqueID. It degrades gracefully.

https://github.com/victronenergy/venus/issues/589

victronenergy/dbus-fronius,victronenergy/dbus-fronius,victronenergy/dbus-fronius,victronenergy/dbus-fronius