Fix DBus connection in Kirigami app

Summary: The device id was not properly passed to the interface factory, rendering the Mpris and mousepad UI useless

Test Plan: Mpris and mousepad UI in app are now actually filled with content

Reviewers: KDE Connect, apol

Reviewed By: KDE Connect, apol

Subscribers: KDE Connect

Tags: KDE Connect

Differential Revision: https://phabricator.kde.org/D12505