[ForCausalLMLoss] allow users to pass shifted labels (#36607)
* [ForCausalLMLoss] allow users to pass shifted labels
Signed-off-by: Stas Bekman <stas@stason.org>
* style
Signed-off-by: Stas Bekman <stas@stason.org>
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Signed-off-by: Stas Bekman <stas@stason.org>