Color sensor ambient and reflected colors don't poll for changes

[samelhusseini]

Looking at the code, we only query for changes of the color sensor when the mode is set to Color, and not for AmbientLightIntensity or ReflectedLightIntensity.

@cait1inhennessy have you verified that the ambient and reflected colors work on the physical device? If so, I'm struggling to explain why..

see: https://github.com/Microsoft/pxt-ev3/blob/master/libs/color-sensor/color.ts#L82