[Flax] Correct all return tensors to numpy (#13307)

* fix_torch_device_generate_test

* remove @

* finish find and replace

tests/test_modeling_flax_bart.py

@@ -453,7 +453,7 @@ class FlaxBartModelTest(FlaxModelTesterMixin, unittest.TestCase, FlaxGenerationT
             padding="max_length",
             truncation_strategy="only_first",
             truncation=True,
-            return_tensors="jax",
+            return_tensors="np",
         )
 
         self.assertEqual(1024, dct["input_ids"].shape[1])