"Associate common file types" and "Launch QtC" should be preselected in QtC offline installers at least

With the new installer framework setup, these checkboxes were made off by default, which at least for the "Launch" question might makes sense for the Qt Online Installer, though I'm not so sure about the "Associate file types" question (why should c++ files not be associated with Qt Creator by default if that is installed?)

But for the Qt Creator (or QDS, basically "single product") offline installers having them off by default doesn't make sense to me.