Add trust_remote_code=True to a few BHASA scenarios

[yifanmai]

• The Hugging Face datasets for facebook/flores, ai4bharat/IndicQA, ai4bharat/IndicSentiment and tmu-nlp/thai_toxicity_tweet contain custom data loaders. In future versions of datasets, trust_remote_code=True will be required to run these custom data loaders. We add trust_remote_code=True for these datasets for future-proofing.
• We pin the revision for these datasets to prevent code injection attacks.
• The dataset thai_toxicity_tweet redirects to tmu-nlp/thai_toxicity_tweet, so we change the name to the canonical name. In general, top level Hugging Face object URLs are being deprecated.

[yifanmai]

cc @raileymontalan @weiqipedia