Reduce atol values in test_dynamic_cache_exportability
Author: st81
Pull request: yes

# What does this PR do?

The `atol` values were increased in #39412, but this change doesn't actually increase the difference between original and exported model key value layers. The logits `atol` was also set too high at 1e-5 when 1e-7 is sufficient.

After this change, the test still passes.

```sh
$ python3 -m pytest tests/utils/test_cache_utils.py  -k test_dynamic_cache_exportability
======================================================================================= test session starts ========================================================================================
platform linux -- Python 3.12.11, pytest-8.4.1, pluggy-1.6.0
rootdir: /home/shutotakahashi/projects/transformers-uv/transformers
configfile: pyproject.toml
collected 61 items / 59 deselected / 2 selected                                                                                                                                                    

tests/utils/test_cache_utils.py::CacheExportIntegrationTest::test_dynamic_cache_exportability PASSED                                                                                         [ 50%]
tests/utils/test_cache_utils.py::CacheExportIntegrationTest::test_dynamic_cache_exportability_multiple_run PASSED       
```

## Before submitting
- [ ] This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
- [x] Did you read the [contributor guideline](https://github.com/huggingface/transformers/blob/main/CONTRIBUTING.md#create-a-pull-request),
      Pull Request section?
- [ ] Was this discussed/approved via a Github issue or the [forum](https://discuss.huggingface.co/)? Please add a link
      to it if that's the case.
- [ ] Did you make sure to update the documentation with your changes? Here are the
      [documentation guidelines](https://github.com/huggingface/transformers/tree/main/docs), and
      [here are tips on formatting docstrings](https://github.com/huggingface/transformers/tree/main/docs#writing-source-documentation).
- [ ] Did you write any new necessary tests?


## Who can review?

- @vasqu
- generate: @zucchini-nlp

Comments:
It looks like changed tests are failed in CI. I will investigate it. 

hey @st81 , that is probably related to hardware and the diffs are actually higher when running the test in our runners :)

@zucchini-nlp Thank you for your feedback! The change in #39412 slightly increases the diff, so `atol=1e-7` should be sufficient. Tests pass with this setting in CI. Could you review the changes?

Also, there's an unrelated test failure that passed in the first commit - looks like it might be flaky.
Failed test: https://app.circleci.com/pipelines/github/huggingface/transformers/139547/workflows/e779ed32-f3c9-49ea-b850-8ff49e19986c/jobs/1848760/steps

```sh
FAILED tests/trainer/test_trainer.py::TrainerIntegrationWithHubTester::test_push_to_hub_with_revision - huggingface_hub.errors.BadRequestError: (Request ID: Root=1-68841c4d-227c4b7537d5ffb65b67ac7a;0d116056-5371-4b08-9a6a-4d21fd440c2a)

Bad request for commit endpoint:
Your push was rejected because an LFS pointer pointed to a file that does not exist. For instance, this can happen if you used git push --no-verify to push your changes. Offending file: - model.safetensors - training_args.bin
```

This test was passed in first commit: https://app.circleci.com/pipelines/github/huggingface/transformers/139418/workflows/4fa288a0-deab-4516-9c1e-a4b2eb655880/jobs/1847114/steps
```sh
[gw0] [ 29%] PASSED tests/trainer/test_trainer.py::TrainerIntegrationWithHubTester::test_push_to_hub_with_revision 
```


After the discussion, let's keep 1e-5 though.

Thank you @st81 however for taking care the details in the codebase.