Remove MainMenuDarkeningPanel

[SadPencil]

    /// <summary>
    /// TODO Replace this class with DarkeningPanels.
    /// Handles transitions between the main menu and its sub-menus.
    /// </summary>
    public class MainMenuDarkeningPanel : XNAPanel

MainMenuDarkeningPanel was created when the generic DarkeningPanel didn't exist yet

it is now completely replaced by the usage of the regular DarkeningPanel and DependencyInjection

[github-actions]

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• artifacts-YR.zip
• artifacts-Ares.zip
• artifacts-TS.zip
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