404 dependency typing change fix (#407)

* Removing array stacking that caused typing issue

Author: dmdunla

pyttb/tensor.py

@@ -1391,7 +1391,6 @@ def symmetrize(  # noqa: PLR0912,PLR0915
             combos = []
             for i in range(0, ngrps):
                 combos.append(np.array(list(permutations(grps[i, :]))))
-            combos = np.stack(combos)
 
             # Create all the permutations to be averaged
             combo_lengths = [len(perm) for perm in combos]