[`Quantization`] Add str to enum conversion for AWQ (#27320)
* add str to enum conversion
* fixup
* Apply suggestions from code review
Co-authored-by: amyeroberts <22614925+amyeroberts@users.noreply.github.com>
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Co-authored-by: amyeroberts <22614925+amyeroberts@users.noreply.github.com>