[Terminal Display] Don't hide the search box when scrolling with the keyboard

Summary:
When hitting Shift-Scrollup while having the search box opened, the search
box is closed.

Regression introduced by f93263d6

Test Plan:
Open the search box, then scroll with the keyboard (e.g. with Shift-Scrollup)
The searchbox should not close.

Reviewers: #konsole, anthonyfieroni

Reviewed By: anthonyfieroni

Subscribers: ngraham, anthonyfieroni, konsole-devel

Tags: #konsole

Differential Revision: https://phabricator.kde.org/D16714