chore(prebuilt): add supported input types for model in create_react_agent (#5748)

- **Description:** Update the type annotations in create_react_agent to
allow one to provide a callable for the model that uses bind_tools and
returns a Runnable[LanguageModelInput, BaseMessage]
  - **Issue:** #5739

---------

Co-authored-by: Eugene Yurtsev <eyurtsev@gmail.com>

libs/prebuilt/langgraph/prebuilt/chat_agent_executor.py

@@ -254,6 +254,13 @@ def create_react_agent(
         LanguageModelLike,
         Callable[[StateSchema, Runtime[ContextT]], BaseChatModel],
         Callable[[StateSchema, Runtime[ContextT]], Awaitable[BaseChatModel]],
+        Callable[
+            [StateSchema, Runtime[ContextT]], Runnable[LanguageModelInput, BaseMessage]
+        ],
+        Callable[
+            [StateSchema, Runtime[ContextT]],
+            Awaitable[Runnable[LanguageModelInput, BaseMessage]],
+        ],
     ],
     tools: Union[Sequence[Union[BaseTool, Callable, dict[str, Any]]], ToolNode],
     *,
@@ -287,6 +294,9 @@ def create_react_agent(
             - **Dynamic model**: A callable with signature
               `(state, runtime) -> BaseChatModel` that returns different models
               based on runtime context
+              If the model has tools bound via `.bind_tools()` or other configurations,
+              the return type should be a Runnable[LanguageModelInput, BaseMessage]
+              Coroutines are also supported, allowing for asynchronous model selection.
 
             Dynamic functions receive graph state and runtime, enabling
             context-dependent model selection. Must return a `BaseChatModel`