No way to know whether sound-name hint is supported by notification daemon

There are sound-name hint in the spec: https://gitlab.freedesktop.org/xdg/xdg-specs/-/blob/master/notification/notification-spec.xml#L758-768

At the same time, sound capability description says: https://gitlab.freedesktop.org/xdg/xdg-specs/-/blob/master/notification/notification-spec.xml#L925-932

So, there are no way to know whether sound-name is supported or not and it's not really possible to rely on it.