[Bugfix] Skip processing if extra_state loads as None
<!-- pylint-output-strict-mode-false -->

beep boop 🤖: 🙏 The following files have warnings. In case you are familiar with these, please try helping us to improve the code base.

---

Your code was analyzed with PyLint. The following annotations have been identified:

```
************* Module nemo.export.trt_llm.nemo_ckpt_loader.nemo_file
nemo/export/trt_llm/nemo_ckpt_loader/nemo_file.py:51:0: C0116: Missing function or method docstring (missing-function-docstring)
nemo/export/trt_llm/nemo_ckpt_loader/nemo_file.py:165:0: C0116: Missing function or method docstring (missing-function-docstring)
nemo/export/trt_llm/nemo_ckpt_loader/nemo_file.py:195:0: C0116: Missing function or method docstring (missing-function-docstring)
nemo/export/trt_llm/nemo_ckpt_loader/nemo_file.py:206:0: C0116: Missing function or method docstring (missing-function-docstring)
nemo/export/trt_llm/nemo_ckpt_loader/nemo_file.py:210:0: C0116: Missing function or method docstring (missing-function-docstring)
nemo/export/trt_llm/nemo_ckpt_loader/nemo_file.py:235:0: C0116: Missing function or method docstring (missing-function-docstring)
nemo/export/trt_llm/nemo_ckpt_loader/nemo_file.py:246:0: C0116: Missing function or method docstring (missing-function-docstring)
nemo/export/trt_llm/nemo_ckpt_loader/nemo_file.py:267:0: C0116: Missing function or method docstring (missing-function-docstring)
nemo/export/trt_llm/nemo_ckpt_loader/nemo_file.py:362:0: C0116: Missing function or method docstring (missing-function-docstring)
nemo/export/trt_llm/nemo_ckpt_loader/nemo_file.py:480:0: C0116: Missing function or method docstring (missing-function-docstring)
nemo/export/trt_llm/nemo_ckpt_loader/nemo_file.py:567:0: C0116: Missing function or method docstring (missing-function-docstring)
nemo/export/trt_llm/nemo_ckpt_loader/nemo_file.py:571:0: C0116: Missing function or method docstring (missing-function-docstring)
nemo/export/trt_llm/nemo_ckpt_loader/nemo_file.py:582:0: C0115: Missing class docstring (missing-class-docstring)
nemo/export/trt_llm/nemo_ckpt_loader/nemo_file.py:594:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/export/trt_llm/nemo_ckpt_loader/nemo_file.py:634:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/export/trt_llm/nemo_ckpt_loader/nemo_file.py:671:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/export/trt_llm/nemo_ckpt_loader/nemo_file.py:684:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/export/trt_llm/nemo_ckpt_loader/nemo_file.py:25:0: W0611: Unused import tensorstore (unused-import)

-----------------------------------
Your code has been rated at 9.55/10
```

---

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We wanted to let you know that a [CICD pipeline](https://github.com/NVIDIA/NeMo/actions/runs/12655706950) for this PR just finished successfully

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//cc @pablo-garay @ko3n1g
# What does this PR do ?

Addressing bug on trying to parse scaling factors that load to `None` on exporting a model to TensorRT-LLM:
```
  File "/opt/NeMo/nemo/export/trt_llm/nemo_ckpt_loader/nemo_file.py", line 496, in load_nemo_model
    model = preprocess_scaling_factors_for_local_export(model)
  File "/opt/NeMo/nemo/export/trt_llm/nemo_ckpt_loader/nemo_file.py", line 96, in preprocess_scaling_factors_for_local_export
    value.seek(0)
AttributeError: 'NoneType' object has no attribute 'seek'
```

Applies only to `use_mcore_path=False` case as extra states in Megatron-LM is correctly filtered out [here](https://github.com/NVIDIA/Megatron-LM/blob/df28200e53056604cad1829ec55bb9ba7c555f23/megatron/core/export/trtllm/trtllm_helper.py#L211-L212).

**Collection**: NLP / LLM

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