Improve custom entity handling and add more unit handling

[Pho3niX90]

This commit improves the handling of custom entities, particularly focusing on ensuring the state is not null, undefined, or unknown. It also adds various system features such as conversion from a state to power and auto conversion from a state to kilowatts. In addition, units of electrical current, energy, and power were added to provide spatial and time recognizability context to the measures. This enhancement results in a more detailed and accurate representation of data. It also includes adjustments in energy conversion for better precision and clarity.

possibly fixes: #299

[slipx06]

Nice improvements. Working through it. Thanks

[slipx06]

Note to check logic when autoscale is false as it shows units in kWh When true it shows W

It should default to the unit of measurement provided by the entity

pv1_power_186: sensor.sunsynk_pv1_power

${data.statePV1Power?.toPowerString(config.solar.auto_scale, data.decimalPlaces)}

toPowerString: (scale?: boolean, decimals?: number, invert?: boolean) =>
            scale ?
                Utils.convertValueNew(entity?.state, entity?.attributes?.unit_of_measurement, decimals || 1) :
                `${Utils.toNum(entity?.state, decimals, invert)} ${UnitOfEnergy.KILO_WATT_HOUR}`,

Change to

toPowerString: (scale?: boolean, decimals?: number, invert?: boolean) =>
            scale ?
                Utils.convertValueNew(entity?.state, entity?.attributes?.unit_of_measurement, decimals || 1) :
                `${Utils.toNum(entity?.state, decimals, invert)} ${entity?.attributes?.unit_of_measurement}`,

[slipx06]

Have applied changes and checked both full and compact cards. Please can you also confirm everything working on your end.

[Pho3niX90]

Soz just seeing everything now, will quickly test on my end

[Pho3niX90]

Okay all seems good my side as well