Wrong dirty handling for ApiColorPicker

[usu]

          @usu I couldn't easily fix the picker problem. I did manage to prevent an api request if the value changes from the outside. I think we could fix the dirty problem in a separate PR.

Originally posted by @manuelmeister in #4328 (comment)

Problem not a problem with ApiColorPicker but either with BasePicker or with ApiWrapper in general.

The dirty handling has also been raised in the following issues, so it probably makes sense to look at it more holistically:

• Adjust trim on autosave to keep 1 space char #3875
• ApiWrapper dirty flag handling #2578

[carlobeltrame]

Fixed in #4761 (unless someone manages to reproduce still)