[SettingsCard] Change ActionIcon to utilize IconSource and IconSourceElement

Currently, the `ActionIcon` is an instance of an `IconElement`. This is problematic, because the `IconElement` is a `FrameworkElement`, meaning it cannot be a shared resource, and therefore changing the icon requires a unique value for every instance. This means it cannot be set using styles.

The solution is to replace the `IconElement` with an `IconSource`, however this is a breaking change. As a result, a deprecation plan needs to be made