xwayland: Don't track focus for override redirect windows
Commit b18f788e2e76 broke motif applications by ensuring they could never focus their menus - since then any attempt by an application to focus any window would be met by the window manager immediately refocusing the currently active toplevel window.
Later we loosened the restriction in 9e07d25a to allow clients that received focus from a grab to do so - but motif applications like nedit don't set focus in this way, and remain broken.
This patch drops our focus watching and resetting code for override redirect windows, so clients may focus them. This restores functionality to motif menus.
Fixes #636 (closed) Fixes b18f788e