Address transformers "false-alarm" warning in hybrid chunker

### Requested feature

Address the "false-alarm" message from the transformers library emitted during hybrid chunking & discussed [here](https://github.com/DS4SD/docling-core/issues/119).

This could be done by catching the warning using [this](https://docs.python.org/3/library/warnings.html#testing-warnings).
HuggingFace is using a variant where they emit an additional warning, calling to ignore the previous warning ([ref](https://github.com/search?q=repo%3Ahuggingface%2Ftransformers+%22token+indices+sequence+length+is+longer%22&type=code)).