Add SensorStateClass.TOTAL to "Last meter readering"

[tabro]

Checklist

• [X] I have filled out the template to the best of my ability.
• [X] This only contains 1 feature request (if you have multiple feature requests, open one feature request for each feature request).
• [X] This issue is not a duplicate feature request of previous feature requests.

Is your feature request related to a problem? Please describe.

It is not possible to add the "Last meter reading" as a energy source in the "Energy" panel of home assistant when the state_class is not set.

I have patched this locally to be able to add the sensor as a energy source.

Describe the solution you'd like

Add:

state_class=SensorStateClass.TOTAL,

to the "Last meter reader" sensor, in order to add the sensor as a energy source to the Energy panel.

Describe alternatives you've considered

?

Additional context

Thats all