Function validate_uki_addon_cmdlines 

fn validate_uki_addon_cmdlines(
    boot: &Dir,
    uki_addon_opts: &UkiAddonOpts,
    final_cmdline: &mut Cmdline<'_>,
) -> Result<()>

Make sure of the following

• We don’t see a composefs cmdline in a global addon
• We don’t see multiple composefs comdlines across UKIs and UKI Addons