Fix #109631: Restore default value operator removes redo panel

Inside `wm_operator_finished`, hud_status is set to `CLEAR` after `reset
to default value` operator.  `CLEAR` status further calls
`ED_area_type_hud_clear()` to free the hud region. This happens as
`do_register` is false due to missing `OPTYPE_REGISTER` flag.

Ref: !133761

source/blender/editors/interface/interface_ops.cc

@@ -386,7 +386,7 @@ static void UI_OT_reset_default_button(wmOperatorType *ot)
   /* flags */
   /* Don't set #OPTYPE_UNDO because #operator_button_property_finish_with_undo
    * is responsible for the undo push. */
-  ot->flag = 0;
+  ot->flag = OPTYPE_REGISTER;
 
   /* properties */
   RNA_def_boolean(