Fix battery updates not contributing to sensor availability

[SwoopX]

For power_configuration.cpp, setting the resource item value is changed from resource::setValue() back to resourceItem::setValue(), as it was prior to version 2.13.0. This will ensure internal resource item timestamps are updated upon reception of an attribute report, even upon no value change.

In the end, this will prevent certain sensors to go into unreachable state and bring back some previously seen websocket events.