wayland: Close internal popups instead of hiding

Hiding the QWindow handle confuses QWidget, which results in user
actions menu not showing up on second launch. Might be a Qt bug.

On the other hand, it makes sense to close dismissed popups, so let's do
it.

src/internalwindow.cpp

@@ -378,7 +378,7 @@ bool InternalWindow::hasPopupGrab() const
 
 void InternalWindow::popupDone()
 {
-    m_handle->hide();
+    m_handle->close();
 }
 
 const std::shared_ptr<QOpenGLFramebufferObject> &InternalWindow::fbo() const