Fixing Gpt2 demo failing

[vzeljkovicTT]

Issue: tenstorrent/tt-xla#3291

Problem:
When importing torchvision with ghcr.io/tenstorrent/tt-xla-slim docker image, users encounter a RuntimeError: operator torchvision::nms does not exist due to version incompatibility between torch and torchvision packages.

vzeljkovic@wh-lb-37-special-vzeljkovic-for-reservation-18832:/localdev/vzeljkovic/tt-forge$ pip list | grep -i torch
torch                             2.9.0+cpu
torch-xla                         2.9.0+git061c1e7
torchaudio                        2.9.0
torchvision                       0.24.0
vzeljkovic@wh-lb-37-special-vzeljkovic-for-reservation-18832:/localdev/vzeljkovic/tt-forge$ 
vzeljkovic@wh-lb-37-special-vzeljkovic-for-reservation-18832:/localdev/vzeljkovic/tt-forge$ python
Python 3.11.14 (main, Oct 10 2025, 08:54:03) [GCC 11.4.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
Ctrl click to launch VS Code Native REPL
>>> import torch
>>> import torchvision
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python3.11/dist-packages/torchvision/__init__.py", line 10, in <module>
    from torchvision import _meta_registrations, datasets, io, models, ops, transforms, utils  # usort:skip
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/dist-packages/torchvision/_meta_registrations.py", line 163, in <module>
    @torch.library.register_fake("torchvision::nms")
     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/dist-packages/torch/library.py", line 1063, in register
    use_lib._register_fake(
  File "/usr/local/lib/python3.11/dist-packages/torch/library.py", line 211, in _register_fake
    handle = entry.fake_impl.register(
             ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/dist-packages/torch/_library/fake_impl.py", line 50, in register
    if torch._C._dispatch_has_kernel_for_dispatch_key(self.qualname, "Meta"):
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
RuntimeError: operator torchvision::nms does not exist

Updated torchvision to use the CPU-compatible version that matches the torch installation