title: Remove hacking license tags when mirroring datasets on the Hub
comments: The docs for this PR live [here](https://moon-ci-docs.huggingface.co/docs/datasets/pr_4302). All of your documentation changes will be reflected on that endpoint. The Hub doesn't allow these characters in the YAML tags, and git push fails if you want to push a dataset card containing these characters. Ok, let me rename the bad config names :) I think I can also keep backward compatibility with a warning Almost done with it btw, will submit a PR that shows all the configuration name changes (from a bit more than 20 datasets)
body: Currently, when mirroring datasets on the Hub, the license tags are hacked: removed of characters "." and "$". On the contrary, this hacking is not applied to community datasets on the Hub. This generates multiple variants of the same tag on the Hub. 
  
  I guess this hacking is no longer necessary:
  - it is not applied to community datasets
  - all canonical datasets are validated by maintainers before being merged: CI + maintainers make sure license tags are the right ones
  
  Fix #4298.