Gutenberg uses two different attributes for text colors:
* `style.color.text`, and
* `textColor`
However, the second one is used only when a color from the default
palette is selected AND the post is saved and reloaded.
With this fix we use the human readable string from the default palette
as a CSS variable.
Please note that while Gutenberg correctly assigns the appropriate CSS
class to render the right color, the problem is that if the color is
handled by a class, it can be overridden for example by themes.
See woocommerce/woocommerce-blocks#6492
Also:
* Refactored some composed components into one inclusive HOC,
called `withUpdateButtonAttributes`.
* The HOC `withTransformSingleSelectToMultipleSelect` allows for the wrong
type to be passed to its wrapped component: if a single element is
passed, that is wrapped into an array.
This didn't play well with TypeScript which obviously complains about
the wrong type being passed to the component.
So we now allow for arrays to be passed as props and ignored by the HOC