Setting a custom `http_client` fails with unexpected keyword argument when using `ChatAnthropic`

### Checked other resources - [x] I added a very descriptive title to this issue. - [x] I searched the LangChain documentation with the integrated search. - [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). ### Example Code from langchain_anthropic import ChatAnthropic llm = ChatAnthropic( thinking={ "type": "enabled", "budget_tokens": 1024 }, model="claude-3-7-sonnet-20250219", max_tokens=4096, http_client=httpx.Client() ) ### Error Message and Stack Trace (if applicable) File "test_claude37_langchain.py", line 46, in <module> llm_result = llm.invoke(prompt_result) ^^^^^^^^^^^^^^^^^^^^^^^^^ File "\Lib\site-packages\langchain_core\language_models\chat_models.py", line 285, in invoke self.generate_prompt( File "\Lib\site-packages\langchain_core\language_models\chat_models.py", line 861, in generate_prompt return self.generate(prompt_messages, stop=stop, callbacks=callbacks, **kwargs) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "\Lib\site-packages\langchain_core\language_models\chat_models.py", line 691, in generate self._generate_with_cache( File "\Lib\site-packages\langchain_core\language_models\chat_models.py", line 926, in _generate_with_cache result = self._generate( ^^^^^^^^^^^^^^^ File "\Lib\site-packages\langchain_anthropic\chat_models.py", line 948, in _generate data = self._client.messages.create(**payload) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "\Lib\site-packages\anthropic\_utils\_utils.py", line 275, in wrapper return func(*args, **kwargs) ^^^^^^^^^^^^^^^^^^^^^ TypeError: Messages.create() got an unexpected keyword argument 'htt…