Implement a way to opt-out colorization in ImageIcon

[NikoYuwono]

Fix #11593

Add a flag to give user a way to opt-out colorization in ImageIcon.
Defaults to true to match current behaviour.
Change the opacity handling with Opacity widget to able to handle opacity when shouldRecolor is false.

[HansMuller]

Unfortunately, the same issue exists with ImageIcon's width, height, and opacity parameters. I don't think we'd want to gradually introduce overrides for them, since ImageIcon really doesn't do very much.

It might be simpler to just use Image directly, if the ImageIcon class is getting in the way.

    Semantics(
      label: mySemanticLabel,
      child: Image(
        image: myImage,
        width: myIconSize,
        height: myIconSize,
        fit: BoxFit.scaleDown,
        alignment: Alignment.center,
        excludeFromSemantics: true,
      ),
    );

[Hixie]

This name isn't immediately clear (should recolor what? to what?).

How about honorIconThemeColor or ignoreIconThemeColor or some such?

[Hixie]

we definitely shouldn't use an Opacity to change the opacity of an image. See the docs for Opacity for an alternative way to do it.

[Hixie]

i think the previous state of this test represents what we actually want the behaviour to be for optimal performance

[Hixie]

i think this test title may be backwards? it doesn't seem to match the test

[Hixie]

This is great, thanks for your contribution!

[Hixie]

@NikoYuwono Are you interested in continuing to work on this?

[goderbauer]

@NikoYuwono Are you still planning to come back to this?

[goderbauer]

Closing this for now as the PR has been open for over a month without action. The issue this is fixing is tracked in #11593.