* Dynamically map state class, device class and UoM in ZHA smart energy metering sensor
* Fix some state & device classes and add scaling
* Fix added imperial gallons tests
* Use entity description instead of custom class & add one entity to tests
* Apply code review suggestion
* Scale only when needed
* Revert "Scale only when needed"
This reverts commit a9e0403402.
* Avoid second lookup of entity description
* Change test to not mix sensor types