predeployed-misc: Drop dist-upgrade job for the abandoned predeployed image

A long time ago, when Apertis was not yet Apertis and SAC was its name, the LAVA workers had a pre-deployed image that people could use for quick testing, and this job was used to run apt dist-upgrade on those images to keep them up-to-date.

Now those pre-deployed images are long forgotten, so let's also drop their vestigial remains.