Is your feature request related to a problem? Please describe.
I'm always frustrated when used color picker.

Describe the solution you'd like
After pick color, make color const if it is originally const.

Describe alternatives you've considered
Maybe close to #4978

Additional context

My class:

class ColorList {
  const ColorList({
    this.color = const Color.fromARGB(255, 182, 134, 153), // The default value of an optional parameter must be constant.
  });
}