I don't think there's a ticket for this, if there is I couldn't find it.
It's been some years since mod_assignment was the go-to assignment activity, some years it's been deprecated and disabled-by-default, and while there was value to having it historically for porting forward older courses... I think maybe it's time to let it go?
It could be removed from core, dropped into its own plugin repo on GitHub (or somewhere) so that anyone coming from really old versions can still access it if they really need to, but otherwise taken out of the core.
I'm thinking it would be one less thing sitting around in the plugins area (a tiny UX improvement), but it would also be less steps to run for unit tests etc.
Maybe something to do for 4.0?