Allow using Compose Brush for tint

[Skaldebane]

Hi there! Thanks for the awesome library.

I'm not sure if there's any technical hurdles, but I think replacing the current tints API where we provide multiple HazeTints with an API where HazeTint itself takes a gradient brush would be pretty awesome.

That'll make it easy to customize the gradient, and make the API feel a lot more natural and easier to use.

This is what I envision the API to look like:

hazeChild(...) {
    // single color overload
    tint = HazeTint(
        color = Color.Blue.copy(alpha = .3f),
        blendMode = ...
    )
    // Brush overload
    tint = HazeTint(
        brush = Brush.verticalGradient(
            Color.Green.copy(alpha = .3f),
            Color.Blue.copy(alpha = .3f)
        ),
        blendMode = ...
    )
}

Because it's tedious to add the .copy(alpha = ...) to every color, I'd suggest adding an opacity parameter (to both versions):

hazeChild(...) {
    // single color overload
    tint = HazeTint(
        color = Color.Blue,
        opacity = .3f,
        blendMode = ...
    )
    // Brush overload
    tint = HazeTint(
        brush = Brush.verticalGradient(Color.Green, Color.Blue),
        opacity = .3f,
        blendMode = ...
    )
}

This design would also enable us to define better fallback tints using the same HazeTint class, e.g. replacing a progressive blur with a translucent gradient, but that's a separate issue (#398).

That's all! Would love to hear your thoughts on this, and thanks for the great work!

[chrisbanes]

I think this is better handled at the backward-compatibility layers for mask and/or progressive, which is already covered by #400

[Skaldebane]

Great to see fallback fixed! However, this was more of a general feature about applying a gradient tint to the blur (not fallback).