Fix "Game embedding not available" message on Wayland

[Hilderin]

• Fixes "Game Embedding not available on your OS" EndeavorOS Hyprland #102819

This PR only adjusts the warning message to "Game Embedding not available on your OS" when using Wayland, making it more specific. The previous message was not entirely accurate since the embedding is available on Linux but not on Wayland.

This is the new warning message, I think it could be better but I'm not inspired:

[clayjohn]

I think the message is fine. Its clear and tells the user what to do to avoid the problem

[akien-mga]

Makes sense to me.

How does it behave if the editor runs X11, but the game itself is configured to use Wayland? This would be set in project settings for the game, and would mean trying to embed a Wayland window in the X11 editor. Do we support that scenario?

[Hilderin]

@akien-mga
That is an excellent question! Nobody thought about this situation before! I tested it, and even on Windows, when the selected display server is 'headless,' the Embedded Window was trying to embed a nonexistent window.

I added another warning message when the Display Server in project setting is headless or wayland:

[Repiteo]

Thanks!