Fix test for file not found
# What does this PR do?

The test for file not found in the TensorFlow auto model tests is failing on main as the message does not match exactly (see [here](https://app.circleci.com/pipelines/github/huggingface/transformers/53015/workflows/6ea05b10-a541-46db-bcce-b93dc654610e/jobs/636205)). This PR fixes that.
_The documentation is not available anymore as the PR was closed or merged._<|||||>Merging to have tests passing on main, but I will address any comment in followup PRs :-)