Add support for /responses websocket

### Checked other resources - [x] This is a feature request, not a bug report or usage question. - [x] I added a clear and descriptive title that summarizes the feature request. - [x] I used the GitHub search to find a similar feature request and didn't find it. - [x] I checked the LangChain documentation and API reference to see if this feature already exists. - [x] This is not related to the langchain-community package. ### Package (Required) - [x] langchain - [x] langchain-openai - [ ] langchain-anthropic - [ ] langchain-classic - [ ] langchain-core - [ ] langchain-model-profiles - [ ] langchain-tests - [ ] langchain-text-splitters - [ ] langchain-chroma - [ ] langchain-deepseek - [ ] langchain-exa - [ ] langchain-fireworks - [ ] langchain-groq - [ ] langchain-huggingface - [ ] langchain-mistralai - [ ] langchain-nomic - [ ] langchain-ollama - [ ] langchain-openrouter - [ ] langchain-perplexity - [ ] langchain-qdrant - [ ] langchain-xai - [x] Other / not sure / general ### Feature Description Openai released support for websockets for the /responses API, it's supposed to increase speed, specially in TTFT and tool calling: Relevant resources: https://github.com/openai/openai-python/releases/tag/v2.22.0 https://developers.openai.com/api/docs/guides/websocket-mode/ ### Use Case When using the OpenAI /responses API via the websockets instead of HTTPS ### Proposed Solution Implement support for it. ### Alternatives Considered Not applicable ### Additional Context I'm not sure just updating the dependency to would be enough, or if more work is required ` "openai>=2.22.0,<3.0.0",` https://github.com/langchain-ai/langchain/blob/0b975d4d1ba532d4da16af222824951aeabba9d6/libs/partners/openai/pyproject.toml#L27