Consider `OnStartup` \ `OnExit` methods as valid initialization \ disposal method

[Pretasoc]

In Unit Tests the analyzer treats the setup and teardown methods specially in the sense, that a disposable created in a setup method and disposed in a tear down method do not generate IDISP003 and IDISP006 diagnostics.

In a wpf application, there is a simmilar method pair OnStartup and OnExit. I think it should be valid code, to initialize a disposable in OnStartUp, when its disposed in OnExit. So the following two snippets should be somewhat simmilar:

public class Foo
{
    private IDisposable _foo = null!;
    
    [SetUp]
    public void Setup()
    {
        _foo = new Disposable();
    }
    
    [TearDown]
    public void TearDown()
    {
        _foo.Dispose();
    }
}

public class FooApp : Application 
{
    private IDisposable _foo = null!;
    
    protected override void OnStartup(StartupEventArgs e)
    {
        base.OnStartup(e);
        _foo = new Disposable();
    }
    
    protected override void OnExit(ExitEventArgs e)
    {
        _foo?.Dispose();
        base.OnExit(e);
    }
}