fix(linear_algebra/prod): add missing `of_dual`s in lemma statements (#15750)
fix(linear_algebra/prod): add missing `of_dual`s in lemma statements (#15750)

Without these the lemmas contain nonsense statements of the form `(x : α) ≤ (y : αᵒᵈ)`.







leanprover-community/mathlib,leanprover-community/mathlib