Fix of visual feedback of IDLE/HEATING state when using valve and pwm is zero

[bemobolo]

Issue:
In the current implementation of the hvac_action property the _is_device_active property is used to decide whether the device is active or not.
But _is_device_active property only checks if the (toggle) heating entity state is OFF or ON.
When setting pwm: 0 the heating entity is considered a valve like entity which is able to accept values between 0-100 and therefore it does not have ON/OFF states. As a consequence in pwm: 0 mode the _is_device_active property returns always false -> the hvac_action is always IDLE even if the control_output is above 0 or even when it's 100.
Fix:
There is a branch added to _is_device_active to check whether we're in pwm mode or not (aka. toggle or valve device is used) and if non pwm mode then the return value of the property is based on the float value of the valve device state (ON if state > 0, OFF if state == 0).

[ScratMan]

Hello, thanks for the fix. But "inverted" is useless when state is "analog" 0/100. You should remove the ==0 option and if pm == 0, only return True if state is >0

[bemobolo]

Thank you, I've made the requested changes!