failing huggingface model download in CI

[jeromedockes]

The CI has been failing intermittently due to paraphrase-albert-small-v2 not being found on the huggingface hub

we need to see if switching to a different model helps, and if not host a copy of the smallest model we can find whose license allows it somewhere else and download and use it as a local model in tests, or mock the sentence-transformers library