fix(3p/exwm): port fix for exwm#759

exwm#759 is a long-standing EXWM bug around window focus being
incorrectly assigned when switching frames.

There's a mysterious fix in the comments of that issue, which some
people (e.g. ezemtsov) apparently use successfully for a long time.

I'm tired of this bug, and want to try this fix. There's no actual
open PR with this fix, and there's no comments from the maintainer on
this yet, so this commit can be considered experimental.

Change-Id: I9412c004132d0cbe359f987c8c1e0773e625a429
Reviewed-on: https://cl.tvl.fyi/c/depot/+/9912
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>

third_party/exwm/exwm-layout.el

@@ -207,7 +207,8 @@ See variable `exwm-layout-auto-iconify'."
                                            xcb:ConfigWindow:StackMode)
                        :border-width 0
                        :stack-mode xcb:StackMode:Above))
-    (cl-pushnew xcb:Atom:_NET_WM_STATE_FULLSCREEN exwm--ewmh-state)
+    ;; commented out to work around https://github.com/ch11ng/exwm/issues/759
+    ;; (cl-pushnew xcb:Atom:_NET_WM_STATE_FULLSCREEN exwm--ewmh-state)
     (exwm-layout--set-ewmh-state exwm--id)
     (xcb:flush exwm--connection)
     (set-window-dedicated-p (get-buffer-window) t)