fix: handle omit type in `_remove_not_given()` for litellm model#1893

seratch merged 3 commits intoopenai:mainopenai/openai-agents-python:mainfrom

HareeshBahuleyan:litellm-toolchoice-omit-fixHareeshBahuleyan/openai-agents-python:litellm-toolchoice-omit-fixCopy head branch name to clipboard