feature request: do not display "unavailable"

[wuppiwuppi]

It would be nice have the option of configuring something, when the actual value is "unavailable" and that should not be visible in the ui-card. I know, there are ways to do this by dummy values or templates. But the idea is: the value can be "unavailable" - I just do not want to see that in the gauge card.

In my case it is the solar production. OpenDTU sets power production to "unavailable", because the inverter switches off at night - but I would rather see a "0" instead of "unavailable" which does not even fit into the widget.

Proposal:
A a default value can be configured in case of "unavailable".
Or it can be configured to display the min value instead.