Fix SearchBar font

Summary:
Parent propagates the font to the child,
this was messing up the font used in the SearchBar.

Test Plan: Manually opened the search bar and verified the font.

Reviewers: hindenburg, ngraham, #konsole

Reviewed By: ngraham

Subscribers: konsole-devel

Tags: #konsole

Differential Revision: https://phabricator.kde.org/D14012