Feature Request Description

I think it would be very helpful, to be able to style the color of a ProgressIndicator component in a different way than setting the valueState prop, because that ads a icon next to the progressbar.
I am currently working with this component and noticed that you can style the shadow parts of other components with the part property, but this feature is missing on the progressindicator.

Proposed Solution

The solution to this problem would be to add the part property to the progressbar and the remaining bar.

Proposed Alternatives

An alternative possible solution could be to add a property which allows to hide the icon, if the valueState prop is set to something different than "None"