Allow to pass BibTex as character to drop_name()

[LukasWallrich]

This allows users to copy-paste BibTex from (e.g.) Google Scholar

drop_name("@article{rungta2022geographic,
  title={Geographic Citation Gaps in NLP Research},
  author={Rungta, Mukund and Singh, Janvijay and Mohammad, Saif M and Yang, Diyi},
  journal={arXiv preprint arXiv:2210.14424},
  year={2022}
}")

In that context, it also deals with #49 - while we should prob not edit bib-files here, it seems fair to add a workaround for this interactive use until bib2df addresses the issue?