effects/overview: Close transient children with the close button
If an application has a modal dialog open it is unlikely to honour a close request to the main window.
This gives a UX where the close button can appear to not work especially because our transient children appear very separately in the overview UI.
This patch sends a close request to the transient children first. Not all transient children are modal, but in that case closing the main window would likely close them anyway.
Testing done: Open kwrite and then settings -> configure kwrite
Edited by David Edmundson