Dynamic pages cannot allocate entire vertical space

Commit c9d5b84a9487b6a2a944d224ceab3ddf0c5814d8 introduced a spacer item which is added unconditionally below any dynamic page. Since this spacer item's size policy is to expand vertically, the dynamic page widget can never allocate the entire vertical space.

This is particularly annoying for wizard pages which use some sort of text browser. For instance, a custom license text viewer which uses a QTextBrowser to display a (naturally very elaborate...) license text.