specifically exclude icons in wasm (for now)

[NoSanityHere]

I noticed that icons are about to become a lot easier with this pr, and i while i know icons in wasm are planned, in the meantime i think the icon shouldn't be included in wasm builds to reduce size.
this works: (I'm assuming android and ios don't support icons because it isn't documented and i doubt they would work)

        #[cfg(not(any(target_arch = "wasm32", target_os = "android", target_os = "ios")))] 
        icon: Some(get_icon()),
        #[cfg(any(target_arch = "wasm32", target_os = "android", target_os = "ios"))]
        icon: None,

but isnt particularly pretty, and one of the goals listed is 'Cross platform. Amount of platform specific user code required should be kept as little as possible.'
Personally i would simply add a macro, where you can simply provide an icon file path, and something similar to above is used, but there might be a cleaner way