GPv3: Delete strokes not working from menu

This fails due to wrong/unnecessary invoke callback. Since this operator
does not have any property, `WM_menu_invoke` fails to call exec()
- - -
Steps to Reproduce:
- Add gpv3 stroke -> switch to edit mode
- Topbar -> Grease Pencil menu -> Delete -> Delete

Pull Request: https://projects.blender.org/blender/blender/pulls/120819

source/blender/editors/grease_pencil/intern/grease_pencil_edit.cc

@@ -483,7 +483,6 @@ static void GREASE_PENCIL_OT_delete(wmOperatorType *ot)
   ot->description = "Delete selected strokes or points";
 
   /* Callbacks. */
-  ot->invoke = WM_menu_invoke;
   ot->exec = grease_pencil_delete_exec;
   ot->poll = editable_grease_pencil_poll;