[Misc] remove peft as dependency for prompt models

[prashantgupta24]

This PR aims at removing the dependency on PEFT. I added a simplified version of the load_peft_weights in a utils file.

Based on comments from #8123

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[github-actions]

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[prashantgupta24]

@njhill @mgoin can we merge this now?

[mgoin]

Thanks for the reminder and work!