chore(data/matrix): delete each of the `matrix.foo_hom_map_zero` (#8512)
chore(data/matrix): delete each of the `matrix.foo_hom_map_zero` (#8512)

These can already be found by `simp` since `matrix.map_zero` is a `simp` lemma, and we can manually use `foo_hom.map_matrix.map_zero` introduced by #8468 instead. They also don't seem to be used anywhere in mathlib, given that deleting them with no replacement causes no build errors.



Co-authored-by: Eric Wieser <da64e90baec5d084ce3d8e05f3b022ae6d118ff5@gmail.com>

leanprover-community/mathlib,leanprover-community/mathlib