backends/x11: Remove extra input window for move/resize
This interferes with Gtk 4 client-side decorations, blocking them from receiving ungrab messages.
This can be seen after dragging a Gtk 4 window. The window is unresponsive until clicked again. If a button is under the mouse while dragging, it will remain depressed permanently.
This extra input-only window was added in 2004 for spurious reasons.
Additional Reference: https://gitlab.gnome.org/GNOME/gtk/-/issues/3858
Edited by Brandon Wright