Improve UX of color picker

[planetchili]

Auto-migrated from intel-sandbox/applications.graphics.presentmonservice/issues/234

^{Original creation by planetchili on 2023-05-24 07:05:33+00:00}

Users might be confused when they manipulate the hue of a black color (value ~0) or of a color with alpha ~0 and fail to see a change in the overlay. Current picker is not easily modified. We can consider importing another one, but might be difficult to match the UI theme/language. Creating one from scratch would be time-consuming.