Revert "display: Do not move X11 input focus during grabs"

This patch unfortunately results in situations where it is intended
that the focus change happens while a grab is present (e.g. Alt+tab
popup), resulting in confused focus state.

This commit is reverted in order to try a similar approach at a
different level.

This reverts commit 7531669b4f.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2832>

src/core/display.c

@@ -1469,9 +1469,7 @@ meta_display_set_input_focus (MetaDisplay *display,
   if (meta_display_timestamp_too_old (display, &timestamp))
     return;
 
-
-  if (display->x11_display &&
-      meta_display_windows_are_interactable (display))
+  if (display->x11_display)
     {
       meta_x11_display_set_input_focus (display->x11_display, window,
                                         focus_frame, timestamp);