Add context to kcmodule connection to lambdas

Summary:
configModule outlives KCModuleQML.

BUG: 397894

Test Plan: Compiled

Reviewers: #plasma, broulik, bruns

Reviewed By: #plasma, broulik, bruns

Subscribers: bruns, kde-frameworks-devel

Tags: #frameworks

Differential Revision: https://phabricator.kde.org/D16594