fix(litellm): defer import until model usage#2462

OiPunk wants to merge 2 commits intoopenai:mainopenai/openai-agents-python:mainfrom

OiPunk:codex/openai-agents-610-windows-unicode-importOiPunk/openai-agents-python:codex/openai-agents-610-windows-unicode-importCopy head branch name to clipboard