Dude, why was this open?
Anyway, Dr.Slump and Dragon Ball not only take place in the same universe, but on the same planet.
In canonical maps, games and even games show Dr.Slump's island in the same world as Dragon Ball.
Nor is it simply a "crossover", since they live in the same world and the events are canonical. Since Goku met Arale in the original DB and recognized her in Super.
We even scaled both universes, with Arale with Beerus (the 2-C) as well as Beerus having resistance to toon force because of Arale.
Seriously, regardless of whether it is outilier or not, whether it is valid or not. I don't even know why the canonicity between the two works is being questioned.