Windows: Avoid triggering QPlatformWindow creation when setting app badge

Calling QWindow::winId() will create the platform window if it hasn't
been created yet, which is not what we want.

Change-Id: I9d4ecb863f961fd3cef6d13e27bf175bf55eabcf
Reviewed-by: Mikołaj Boc <Mikolaj.Boc@qt.io>
Reviewed-by: Eirik Aavitsland <eirik.aavitsland@qt.io>

src/plugins/platforms/windows/qwindowsintegration.cpp

@@ -773,6 +773,8 @@ void QWindowsIntegration::setApplicationBadge(const QImage &image)
     // the other windows will take over in showing the badge.
     const auto topLevelWindows = QGuiApplication::topLevelWindows();
     for (auto *topLevelWindow : topLevelWindows) {
+        if (!topLevelWindow->handle())
+            continue;
         auto hwnd = reinterpret_cast<HWND>(topLevelWindow->winId());
         taskbarList->SetOverlayIcon(hwnd, hIcon, L"");
     }