Selecting black and turning opacity to 0 results in alpha being "TRANSPARENT" instead of expected 0
Can be reproduced here: https://casesandberg.github.io/react-color/

When using Sketch Picker, turning the color to black and the opacity to zero results in the hex label displaying `TRANSPARENT` instead of the inspected `#000000`. This also impacts many of the other pickers on this page, even though the selection has to be done using the sketch picker
