TLDR: It doesn't matter to much. They are both very good. But Husky is slightly better.
If you check their stats you will find out that they are both almost identical. They have the same Wildness ration of 0% - so they are both trained fast. Also they can do the same things.
As you can see Husky has better 3 stats. Labrador doesn't have anything better than Husky.
Tested with A16
RimWorld A18 is mostly the same: