Expand Widget Icon Customization

ColinSullivan

Requesting the ability to supply a calcite icon with a size in the Expand Widget.  Something like "chevron-left-24"

Going a step further: it would be great if we could pass it more than a string. A direct reference to a url or a calcite icon reference like below:

import { chevronLeft32 } from '@esri/calcite-ui-icons';