Add correct labels in HF models config

[buhrmann]

Just a suggestion, but e.g. here: https://huggingface.co/cardiffnlp/twitter-roberta-base-emoji/blob/main/config.json, if id2label and label2id were setup correctly, one wouldn't have to separately load the mappings.txt file from this github repo, and do the mapping manually.

[pedrada88]

Thank you for the suggestion! For now, we will have to keep the same labels to be consistent (in case someone is already using the model and expects these labels instead of the correct ones).
In more recent models we did use the right labels without mapping.txt (for example the twitter-xlm-roberta-base-sentiment model - https://huggingface.co/cardiffnlp/twitter-xlm-roberta-base-sentiment)