llama : add support for Tekken pre-tokenizer (#8579)

* llama : Added support for Tekken pre-tokenizer (#8577)

Removed uneeded `vocab.tokenizer_clean_spaces` assignment

* llama : fix order of pre-tokenizers

* * Tekken pre-tokenizer no longer uses clean_up_tokenization_spaces
* Updated chkhsh for Tekken tokenizer

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Co-authored-by: Georgi Gerganov <ggerganov@gmail.com>