Quiz no longer respects questionsperpage default setting

In MDL-67351, the quiz mod form was changed to use mod_form:apply_admin_defaults(), and so the individual default setting were removed from the form.

That worked fine in all except one case, questionsperpage (Layout > New page setting), from what I can tell. The problem is that the questionsperpage is actually contained within a group, questionsperpagegrp, in the form, and apply_admin_defaults() does not recursively check. It only applys the defaults for elements that are at the root level of the form.

So either apply_admin_defaults() needs to be updated to "search" for form elements, or this line needs to be brought back in.

This also applies to the advanced flag for the item, which is actually controlled under the questionsperpagegrp name, since it is the entire group that has that flag. Because of that, this line would also need to come back, since that would not be an easy fix to apply_admin_defaults().