Update unit test to match change to reselecting top entry

Summary:
37014e643cec4ee9aed54421f66c675e1bc91b70 introduced a change in the
behaviour of what happens when you select the top entry in the list.

Change makes some sense. Unit test was not updated, it therefore failed.

Test Plan: Ran unit test

Reviewers: Plasma, mart

Reviewed By: mart

Subscribers: joselema, rikmills, plasma-devel

Tags: Plasma

Differential Revision: https://phabricator.kde.org/D5570