Update plugins.qmltypes for QtQuick.Dialogs

Change-Id: I7e12acab9b958533d3065257f507304984f117d2
Reviewed-by: Fawzi Mohamed <fawzi.mohamed@digia.com>
Reviewed-by: Liang Qi <liang.qi@digia.com>
Update plugins.qmltypes for QtQuick.PrivateWidgets

Change-Id: I53236f5698b2430e533d94ebb146beb72ce49c21
Reviewed-by: Fawzi Mohamed <fawzi.mohamed@digia.com>
Reviewed-by: Liang Qi <liang.qi@digia.com>