Update example to flush OnStop

[snakefoot]

Update the example code to force flush on OnStop:

• https://learn.microsoft.com/en-us/dotnet/maui/fundamentals/app-lifecycle?view=net-maui-9.0

using Microsoft.Maui.LifecycleEvents;

namespace PlatformLifecycleDemo
{
    public static class MauiProgram
    {
        public static MauiApp CreateMauiApp()
        {
            var builder = MauiApp.CreateBuilder();
            builder
                .UseMauiApp<App>()
                .ConfigureLifecycleEvents(events =>
                {
#if IOS || MACCATALYST
                    events.AddiOS(ios => ios
                        .OnActivated((app) => LogEvent(nameof(iOSLifecycle.OnActivated)))
                        .OnResignActivation((app) => LogEvent(nameof(iOSLifecycle.OnResignActivation)))
                        .DidEnterBackground((app) => LogEvent(nameof(iOSLifecycle.DidEnterBackground)))
                        .WillTerminate((app) => LogEvent(nameof(iOSLifecycle.WillTerminate))));
#endif
                    static bool LogEvent(string eventName, string type = null)
                    {
                        NLog.LogManager.Info($"Lifecycle event: {eventName}{(type == null ? string.Empty : $" ({type})")}");
                        NLog.LogManager.Flush();
                        return true;
                    }
                });

            return builder.Build();
        }
    }
}

Mostly important if depending on async-wrapper or network-targets (eMail / Syslog / Graylog / Database etc.)

If just using pure console-target and file-target without any wrappers, then everything is synchronous and no bonus flush needed.