[FluentSplashScreen] Fix ESC on SplashScreen

[dvoituron]

[FluentSplashScreen] Fix ESC on SplashScreen

The DialogService.ShowSplashScreenAsync method did not apply the PreventDismissOnOverlayClick parameter.
This PR corrects this problem:

DialogParameters<SplashScreenContent> parameters = new()
{
    Content = new()
    {
        DisplayTime = 0,    // See Task.Delay below
        Title = "Core components",
        SubTitle = "Microsoft Fluent UI Blazor library",
        LoadingText = "Loading...",
        Message = (MarkupString)"some <i>extra</i> text <strong>here</strong>",
        Logo = FluentSplashScreen.LOGO,
    },
    PreventDismissOnOverlayClick = true,  // 👈 Set this line to avoid closing SplashScreen with ESC
    Width = "640px",
    Height = "480px",
};
_dialog = await DialogService.ShowSplashScreenAsync(parameters);

Fix #1803