Skip flaky NLLB Moe test for now
# What does this PR do?

Skips flaky test. See failed CI run here: https://app.circleci.com/pipelines/github/huggingface/transformers/60931/workflows/4642cd50-8d8c-4a6b-bea9-b077ff7400cf/jobs/747651


## Before submitting
- [ ] This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
- [ ] Did you read the [contributor guideline](https://github.com/huggingface/transformers/blob/main/CONTRIBUTING.md#start-contributing-pull-requests),
      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?
cc @sgugger @ArthurZucker <|||||>_The documentation is not available anymore as the PR was closed or merged._<|||||>Thanks Amy!