`.aspectRatio` doesn't apply to AsyncImage placeholder

[dfabulich]

Add this playground to the ImagePlayground:

HStack {
    Text("Failed URL\n.aspectRatio(3/4)")
    Spacer()
    AsyncImage(url: URL(string: "file:///does_not_exist.png")!)
        .aspectRatio(3.0/4.0, contentMode: .fit)
        .border(Color.blue)
}

Expected: You should see a 3x4 placeholder rectangle

Actual: The placeholder doesn't appear (it renders 0x0)