Fix error in WaylandSurface::testDisconnect
Summary:
This test deletes the client wayland connection.
We then finish the test and call test cleanup which
releases m_idleInhititManager.
Calling release after the connection is destroyed is an error.
Hence the explicit destroy.
Test Plan:
Built tests with ASAN
No more crash
Reviewers: Plasma, graesslin
Reviewed By: Plasma, graesslin
Subscribers: plasma-devel, Frameworks
Tags: Frameworks, Plasma
Differential Revision: https://phabricator.kde.org/D9402