update to_py_obj to support np.number (#14064)

Co-authored-by: 眸浩 <mouhao.zm@alibaba-inc.com>

src/transformers/file_utils.py

@@ -1946,7 +1946,7 @@ def to_py_obj(obj):
         return obj.detach().cpu().tolist()
     elif is_flax_available() and _is_jax(obj):
         return np.asarray(obj).tolist()
-    elif isinstance(obj, np.ndarray):
+    elif isinstance(obj, (np.ndarray, np.number)):  # tolist also works on 0d np arrays
         return obj.tolist()
     else:
         return obj