Temperature dropped from responses api payload with gpt-5.2 default reasoning effort

### Checked other resources - [x] This is a bug, not a usage question. - [x] I added a clear and descriptive title that summarizes this issue. - [x] I used the GitHub search to find a similar question and didn't find it. - [x] I am sure that this is a bug in LangChain rather than my code. - [x] The bug is not resolved by updating to the latest stable version of LangChain (or the specific integration package). - [x] This is not related to the langchain-community package. - [x] I posted a self-contained, minimal, reproducible example. A maintainer can copy it and run it AS IS. ### Package (Required) - [ ] 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 - [ ] Other / not sure / general ### Related Issues / PRs _No response_ ### Reproduction Steps / Example Code (Python) ```python model = ChatOpenAI( model="gpt-5.2", use_responses_api=True, temperature=0.5, ) model.invoke([{"role": "user", "content": "Hello, world"}]) ``` ### Error Message and Stack Trace (if applicable) ```shell DEBUG:openai._base_client:Request options: {'method': 'post', 'url': '/responses', 'headers': {'X-Stainless-Raw-Response': 'true'}, 'files': None, 'idempotency_key': 'stainless-python-retry-9a86afe9-a319-4db8-b386-d974747f84fe', 'content': None, 'json_data': {'input': [{'content': 'Hello, world', 'role': 'user'}], 'model': 'gpt-5.2', 'stream': False}} ``` ### Description Temperature is supported in newer (5.x) openai models as long as reasoning is disabled. With gpt-5.2, the default reasoning effort is `none`, so the temperature parameter s…