Backwards compatibility handling on last_event for button and relative_rotary

[idekker]

Added code to handle the case where the bridge only emits the deprecated last_event property and not button_report (or relative_rotary). Also created a test for it.

I do wonder whether this code has to move to the ButtonController (and RelativeRotaryController) class before _handle_event on the base class is called, including the code that drops update-events that do not have a report. But I'm not sure if any of the code that is after super()._handle_event(...) is still relevant even if we decided not to inject the event/new resource upstream.