v4.57.1

This patch most notably fixes an issue with an optional dependency (optax), which resulted in parsing errors with poetry. It contains the following fixes:

• fix optax dep issue
• remove offload_state_dict from kwargs
• Fix bnb fsdp loading for pre-quantized checkpoint (#41415)
• Fix tests fsdp (#41422)
• Fix trainer for py3.9 (#41359)