codegen: org.freedesktop.sysupdate1 interface is missing

A new `org.freedesktop.sysupdate1` interface has been added to the `systemd` suite in https://github.com/systemd/systemd/pull/32363. It will be first released in next major upstream version (`257`). This is a reminder to add the relevant codegen config and generate the new `sysupdate1` module, once the new upstream release is out.