Incorrect parameter passing for metadata in the langchain-js framework

[Wyatex]

In langchain-js versions after v1.0, parameters can no longer be passed to the CallbackHandler constructor. Instead, they should be passed within the invoke method.

Here is the correct approach:

// ...

const langfuseHandler = new CallbackHandler({});

// ...

console.log(
  await agent.invoke(
    {
      messages: [
        { role: "user", content: "What's the weather in San Francisco?" },
      ],
    },
    {
      callbacks: [langfuseHandler],
      metadata: {
        langfuse_session_id: "user-session-123",
        langfuse_user_id: "user-abc",
        langfuse_tags: ["langchain-test"],
      },
    }
  )
);

I think we should highlight the differences in usage between versions before and after v1.0.