TF-OPT attention mask fixes (#25238)
* stash commit
* More OPT updates
* Update src/transformers/models/opt/modeling_tf_opt.py
Co-authored-by: amyeroberts <22614925+amyeroberts@users.noreply.github.com>
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Co-authored-by: amyeroberts <22614925+amyeroberts@users.noreply.github.com>
