[Doctest] Add `configuration_wavlm.py`
Add configuration_wav2vec2_conformer.py to utils/documentation_tests.txt for doctest.

Based on issue: [19487](https://github.com/huggingface/transformers/issues/19487)


@ydshieh Could you please take a look? Thank you very much for your kind support!
_The documentation is not available anymore as the PR was closed or merged._