iOS: don't activate non-toplevel windows

Parts of the code seems to assume that all QWindows are
top-level windows. This will be false when not using
alien, as then, each widget will be wrapped inside a
QWidgetWindow. In that case, we should not tell QPA to
activate the "window".

This bug caused focus handling (and text input) to fall
apart for e.g graphicsview when using a QGLWidget as viewport.

Change-Id: I579db7a84d718973e02e96ed535fe6e25baf4bd5
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@digia.com>

src/plugins/platforms/ios/qioswindow.mm

@@ -407,7 +407,7 @@ void QIOSWindow::requestActivateWindow()
     // Note that several windows can be active at the same time if they exist in the same
     // hierarchy (transient children). But only one window can be QGuiApplication::focusWindow().
     // Dispite the name, 'requestActivateWindow' means raise and transfer focus to the window:
-    if (blockedByModal())
+    if (!window()->isTopLevel() || blockedByModal())
         return;
 
     raise();