Granite 3.2 Thinking

### Checked other resources

- [x] This is a bug, not a usage question. For questions, please use GitHub Discussions.
- [x] I added a clear and detailed title that summarizes the issue.
- [x] I read what a minimal reproducible example is (https://stackoverflow.com/help/minimal-reproducible-example).
- [x] I included a self-contained, minimal example that demonstrates the issue INCLUDING all the relevant imports. The code run AS IS to reproduce the issue.

### Example Code

```python
from langgraph.prebuilt import create_react_agent

def build_ollama_llm(model:str = OLLAMA_CHAT_MODEL) -> ChatOllama:
    return ChatOllama(
        base_url    = OLLAMA_BASE_URL,
        model       = model,
        temperature = OLLAMA_TEMPERATURE,
        seed        = OLLAMA_SEED,
        format      = "",
        verbose     = OLLAMA_CHAT_FUNCTION_VERBOSE,
        disable_streaming = True,
        keep_alive  = 0
    )

def build_react_agent(model):
    logger.info('Creating ReAct Agent')
    return create_react_agent(
        model        = model,
        tools        = TOOLS_LIST,
        checkpointer = memory,
        name         = "ReAct_Agent_WIP",
        debug        = REACT_AGENT_VERBOSE
    )

llm = build_ollama_llm()
agent_supervisor = build_react_agent(llm)

messages_with_think = {
            "messages": [
                {
                    "role": "control",
                    "content": "thinking"
                },
                (
                    "user",
                    question,
                )
            ]
}

if "granite3.2" in OLLAMA_CHAT_MODEL:
    messages = messages_with_think

async for event in agent_supervisor.astream(
    input = messages,
    config = config,
    stream_mode = "values",
    debug = OPENAI_SUPERVISOR_VERBOSE
):
    logger.debug(event)
```

### Error Message and Stack Trace (if applicable)

```shell
Traceback (most recent call last):
  File "c:\react_WIP.py", line 945, in astream_interactive
    async for event in agent_supervisor.astream(
  File "c:\Users\user\AppData\Local\Programs\Python\Python312\Lib\site-packages\langgraph\pregel\__init__.py", line 2304, in astream  
    while loop.tick(input_keys=self.input_channels):
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "c:\Users\user\AppData\Local\Programs\Python\Python312\Lib\site-packages\langgraph\pregel\loop.py", line 419, in tick
    mv_writes = apply_writes(
                ^^^^^^^^^^^^^
  File "c:\Users\user\AppData\Local\Programs\Python\Python312\Lib\site-packages\langgraph\pregel\algo.py", line 305, in apply_writes
    if channels[chan].update(vals) and get_next_version is not None:
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "c:\Users\user\AppData\Local\Programs\Python\Python312\Lib\site-packages\langgraph\channels\binop.py", line 88, in update
    self.value = self.operator(self.value, value)
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "c:\Users\user\AppData\Local\Programs\Python\Python312\Lib\site-packages\langgraph\graph\message.py", line 36, in _add_messages
    return func(left, right, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "c:\Users\user\AppData\Local\Programs\Python\Python312\Lib\site-packages\langgraph\graph\message.py", line 173, in add_messages
    for m in convert_to_messages(right)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "c:\Users\user\AppData\Local\Programs\Python\Python312\Lib\site-packages\langchain_core\messages\utils.py", line 364, in convert_to_messages
    return [_convert_to_message(m) for m in messages]
            ^^^^^^^^^^^^^^^^^^^^^^
  File "c:\Users\user\AppData\Local\Programs\Python\Python312\Lib\site-packages\langchain_core\messages\utils.py", line 337, in _convert_to_message
    _message = _create_message_from_message_type(
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "c:\Users\user\AppData\Local\Programs\Python\Python312\Lib\site-packages\langchain_core\messages\utils.py", line 289, in _create_message_from_message_type
    raise ValueError(msg)
ValueError: Unexpected message type: 'control'. Use one of 'human', 'user', 'ai', 'assistant', 'function', 'tool', 'system', or 'developer'.
For troubleshooting, visit: https://python.langchain.com/docs/troubleshooting/errors/MESSAGE_COERCION_FAILURE
```

### Description

I'm trying to use create_react_agent with Granite3.2 with Thinking

### System Info

langchain_ollama     version: 0.2.3
langchain_core       version: 0.3.41
langchain_community  version: 0.3.19
langchain_openai     version: 0.2.12
langgraph            version: 0.3.5
langsmith            version: 0.3.11

State: closed