fix for itemsize => element_size() for torch backwards compat (#30133)
* fix for itemsize => element_size() for torch backwards compat
* improve handling of element counting
* Update src/transformers/modeling_utils.py
* fixup
* Update src/transformers/modeling_utils.py
Co-authored-by: amyeroberts <22614925+amyeroberts@users.noreply.github.com>
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Co-authored-by: Younes Belkada <49240599+younesbelkada@users.noreply.github.com>
Co-authored-by: Younes Belkada <younesbelkada@gmail.com>
Co-authored-by: amyeroberts <22614925+amyeroberts@users.noreply.github.com>