QmlDesigner: Do not crash if EditView3D contains errors

EditView3D.qml can contain errors, most likely because
of QtQuick3D updates.

Change-Id: I85879d9079ba8771a2af4478ba2e4e63a6aa9223
Reviewed-by: Miikka Heikkinen <miikka.heikkinen@qt.io>

share/qtcreator/qml/qmlpuppet/qml2puppet/instances/qt5informationnodeinstanceserver.cpp

@@ -84,6 +84,11 @@ static QObject *createEditView3D(QQmlEngine *engine)
 
     QWindow *window = qobject_cast<QWindow *>(component.create());
 
+    if (!window) {
+        qWarning() << "Could not create edit view" << component.errors();
+        return nullptr;
+    }
+
     //For macOS we have to use the 4.1 core profile
     QSurfaceFormat surfaceFormat = window->requestedFormat();
     surfaceFormat.setVersion(4, 1);
@@ -193,6 +198,9 @@ void Qt5InformationNodeInstanceServer::setup3DEditView(const QList<ServerNodeIns
     if (node) { // If we found a scene we create the edit view
         QObject *view = createEditView3D(engine());
 
+        if (!view)
+            return;
+
         QQmlProperty sceneProperty(view, "scene", context());
         node->setParent(view);
         sceneProperty.write(objectToVariant(node));