find org.kde.kirigami as runtime dependency

Summary:
without it the energy and indexer modules won't work.

BUG: 403011
FIXED-IN: 5.18.0

Test Plan: org.kde.kirigami listed as runtime dep and reported missing when not installed

Reviewers: broulik, ngraham

Reviewed By: ngraham

Subscribers: plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D26789