lokdialog: Call LOK invalidate explicitly here

In some cases, Window::Update is called directly by the child classes.
This is not good for LOK clients because they rely on 'invalidate'
callbacks for painting the window.

Change-Id: I05402d7597841c96a25b7f5ac4cc60dda6ec5a16
(cherry picked from commit a39cefd9)

vcl/source/window/paint.cxx

@@ -1319,6 +1319,7 @@ void Window::Update()
          }
 
         pUpdateWindow->ImplCallPaint(nullptr, pUpdateWindow->mpWindowImpl->mnPaintFlags);
+        pUpdateWindow->LogicInvalidate(nullptr);
 
         if (xWindow->IsDisposed())
            return;