Fix expected value in tests of the test fetcher
# What does this PR do?

#24051 broke a test in the test suite of the test fecther. The PR did not run the CI because the modification was detected as a docstring modification. This is due to a """ in the middle of the file that this PR also fixes.
The docs for this PR live [here](https://moon-ci-docs.huggingface.co/docs/transformers/pr_24077). All of your documentation changes will be reflected on that endpoint.