[Bugfix] Fix get tokenizer error when passing a local_path

[Potabk]

What does this PR do?

Fixes # (issue)

Fix AttributeError: 'dict' object has no attribute 'model_type'. When I'm using transformers==4.57.2, I encountered the following issue:

>>> tokenizer = AutoTokenizer.from_pretrained("/models/Qwen/Qwen2___5-0___5B-Instruct")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/python3.11.13/lib/python3.11/site-packages/transformers/models/auto/tokenization_auto.py", line 1156, in from_pretrained
    return tokenizer_class.from_pretrained(pretrained_model_name_or_path, *inputs, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/python3.11.13/lib/python3.11/site-packages/transformers/tokenization_utils_base.py", line 2112, in from_pretrained
    return cls._from_pretrained(
           ^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/python3.11.13/lib/python3.11/site-packages/transformers/tokenization_utils_base.py", line 2419, in _from_pretrained
    if _is_local and _config.model_type not in [
                     ^^^^^^^^^^^^^^^^^^
AttributeError: 'dict' object has no attribute 'model_type'

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[Solenhya]

Hahaha i just stumble upon the same issue. From what i have seen the issue is that when there is a cached config_file we are json loading a file and that can only give at best a dict not the usual config object :

                if _config_file is not None:
                    with open(_config_file, encoding="utf-8") as f:
                        _config = json.load(f)
                    transformers_version = _config.get("transformers_version")
                    if transformers_version and version.parse(transformers_version) <= version.parse("4.57.2"):
                        if _is_local and _config.model_type not in [
                            "mistral",
                            "mistral3",
                            "voxstral",
                            "ministral",
                            "pixtral",
                        ]:
                            return tokenizer

[Potabk]

#42389 will fix it