macOS Tahoe: How to properly use transparent icons with system theme

I never use mac and had never experimented with the macOS theme before updating my build machine to Tahoe, but now I see that the transparent background looks poor.

I see the note in the README about not using transparent borders, but I am not sure that applies to this macOS topic.

The Chrome and VSCode icons use either black or white as the icon background depending on the macOS theme settings. Is there a way to use use either black or white as the background for my flutter icon?

This is the 500x500 PNG icon exported from the original SVG.

And my `flutter_launcher_icons.yaml`
```yaml
# dart run flutter_launcher_icons
flutter_launcher_icons:
image_path: "assets/icon/icon.png"

windows:
generate: true
image_path: "assets/icon/icon.png"

macos:
generate: true
image_path: "assets/icon/icon.png"
```