Anything for the other platforms at all?

@jamesmontemagno Windows & Android are using bytes for their "platform colors" so the bytes from the "system color" can be used 1:1

Should also add some tests -> https://github.com/xamarin/Essentials/blob/main/Tests/Color_Tests.cs

Just spent an hour trying to add tests but the solution wouldn't build on my VS4Mac and on Windows, VS kept freezing when trying to start a remote session or the iOS simulator wouldn't launch.

This was the test I intended to try:

#if __IOS__
        [Fact]
        public void PlatformToColorDecimal()
        {
            var platform = UIKit.UIColor.FromDisplayP3(101.999986320734f, 50.9999969601631f, 153.000021278858f, a);
            var hex_platform = platform.ToString();
            var system = platform.ToSystemColor();
            var hex_system = system.ToString();
            Assert.Equal(hex_platform, hex_system);
        }
#endif

@mattleibow good to go?