tool/transform: fixes the awkward space in tool options Summary: The size of the vertical spacer was probably disturbed while I was working the cage transform options, this patch should fix it.

BUG:403591
Reviewers: Krita, woltherav
Reviewed By: Krita, woltherav
Subscribers: Krita
Tags: Krita

Differential Revision: https://phabricator.kde.org/D18524