Item.sendCommandIfDifferent should handle conversion from JS Number to QuantityType

[wertzui]

Item.sendCommandIfDifferent(value) is an easy way to only send updates if something changed.

However if the items state is a QuantityType and the value is a Number or a String without a quantity, this method always detects a change.
This is, because it compares the strings directly and if for example the state returns 26 °C and the value is 26, these are different.

It would be good if this method handles such cases and if value is a number, it just compares the number of the state and not the value too.