dnd: Avoid sync_pointer after pop_modal()

This is only necessary for the X11 backend (as grabs triggered by other
clients leave GNOME Shell oblivious of the actual pointer position), but
is now handled inside Mutter.

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1556>

js/ui/dnd.js

@@ -770,7 +770,6 @@ var _Draggable = class _Draggable {
             Shell.util_set_hidden_from_pick(this._dragActor, false);
 
         this._ungrabEvents();
-        global.sync_pointer();
 
         if (this._updateHoverId) {
             GLib.source_remove(this._updateHoverId);