Port kolourpaint away from Kdeprint::createPrintDialog

Summary: This was the final step to port away from kdelibs4support.

Test Plan: The print dialog still has the 3rd widget with 2 radiobuttons like before.

Reviewers: broulik, andreagenor, tcanabrava, vkrause

Reviewed By: vkrause

Maniphest Tasks: T11576

Differential Revision: https://phabricator.kde.org/D25601