Merge pull request #285976 from natsukium/safetensors/fix-darwin

python311Packages.safetensors: fix build on darwin

pkgs/development/python-modules/safetensors/default.nix

···
     "tests/test_flax_comparison.py"
     "tests/test_paddle_comparison.py"
     "tests/test_tf_comparison.py"
+  ] ++ lib.optionals stdenv.isDarwin [
+    # don't require mlx (not in Nixpkgs) to run tests
+    "tests/test_mlx_comparison.py"
   ];
 
   pythonImportsCheck = [