chore: remove duplicated MulDistribMulAction instances

[dwrensha]

There are currently three identical copies of the same instance:

FLT/FLT/Deformations/RepresentationTheory/Etale.lean

Lines 465 to 514 in 77275f8

	noncomputable
	instance {A : Type*} [CommRing A] [Bialgebra K A] :
	MulDistribMulAction (L ≃ₐ[K] L) (A →ₐ[K] L) where
	smul_mul r f g := by
	ext x
	change r (Algebra.TensorProduct.lift _ _ (fun _ _ ↦ .all _ _) (Coalgebra.comul x)) =
	Algebra.TensorProduct.lift _ _ (fun _ _ ↦ .all _ _) (Coalgebra.comul x)
	induction Coalgebra.comul (R := K) x with
	| zero => simp only [map_zero]
	| add x y _ _ => simp only [map_add, *]
	| tmul x y => simp; rfl
	smul_one r := by
	ext x
	change r (algebraMap _ _ _) = _
	simp
	rfl
	noncomputable
	instance {A : Type*} [CommRing A] [Bialgebra K A] :
	MulDistribMulAction (L ≃ₐ[K] L) (A →ₐ[K] L) where
	smul_mul r f g := by
	ext x
	change r (Algebra.TensorProduct.lift _ _ (fun _ _ ↦ .all _ _) (Coalgebra.comul x)) =
	Algebra.TensorProduct.lift _ _ (fun _ _ ↦ .all _ _) (Coalgebra.comul x)
	induction Coalgebra.comul (R := K) x with
	| zero => simp only [map_zero]
	| add x y _ _ => simp only [map_add, *]
	| tmul x y => simp; rfl
	smul_one r := by
	ext x
	change r (algebraMap _ _ _) = _
	simp
	rfl
	noncomputable
	instance {A : Type*} [CommRing A] [Bialgebra K A] :
	MulDistribMulAction (L ≃ₐ[K] L) (A →ₐ[K] L) where
	smul_mul r f g := by
	ext x
	change r (Algebra.TensorProduct.lift _ _ (fun _ _ ↦ .all _ _) (Coalgebra.comul x)) =
	Algebra.TensorProduct.lift _ _ (fun _ _ ↦ .all _ _) (Coalgebra.comul x)
	induction Coalgebra.comul (R := K) x with
	| zero => simp only [map_zero]
	| add x y _ _ => simp only [map_add, *]
	| tmul x y => simp; rfl
	smul_one r := by
	ext x
	change r (algebraMap _ _ _) = _
	simp
	rfl

These were added in #615

This PR removes two of them.

[kbuzzard]

Thanks!