efl_ui_focus_manager_sub: remove event callback array when destructing

i forgot about that and this leads to a segfault in enlightenment, the
object then segfaults when the parent manager emits a event and then the
code tries to access the private data of a dead object.

src/lib/elementary/efl_ui_focus_manager_sub.c

@@ -203,6 +203,8 @@ _efl_ui_focus_manager_sub_efl_object_destructor(Eo *obj, Efl_Ui_Focus_Manager_Su
 {
    _border_unregister(obj, pd);
 
+   efl_event_callback_array_del(pd->manager, parent_manager(), obj);
+
    efl_destructor(efl_super(obj, MY_CLASS));
 }