FIX [Gemma / CI] Make sure our runners have access to the model (#29242)

* pu hf token in gemma tests

* update suggestion

* add to flax

* revert

* fix

* fixup

* forward contrib credits from discussion

---------

Co-authored-by: ArthurZucker <ArthurZucker@users.noreply.github.com>

src/transformers/testing_utils.py

@@ -31,12 +31,14 @@ import time
 import unittest
 from collections import defaultdict
 from collections.abc import Mapping
+from functools import wraps
 from io import StringIO
 from pathlib import Path
 from typing import Callable, Dict, Iterable, Iterator, List, Optional, Union
 from unittest import mock
 from unittest.mock import patch
 
+import huggingface_hub
 import urllib3
 
 from transformers import logging as transformers_logging
@@ -460,6 +462,20 @@ def require_torch_sdpa(test_case):
     return unittest.skipUnless(is_torch_sdpa_available(), "test requires PyTorch SDPA")(test_case)
 
 
+def require_read_token(fn):
+    """
+    A decorator that loads the HF token for tests that require to load gated models.
+    """
+    token = os.getenv("HF_HUB_READ_TOKEN", None)
+
+    @wraps(fn)
+    def _inner(*args, **kwargs):
+        with patch(huggingface_hub.utils._headers, "get_token", return_value=token):
+            return fn(*args, **kwargs)
+
+    return _inner
+
+
 def require_peft(test_case):
     """
     Decorator marking a test that requires PEFT.