fix: add token usage

[desaxce]

Changes:

• add token usage for LangChain

To test:

• Run the following snippet against a Literal AI project and notice token counts:

import os
from literalai import LiteralClient

from langchain_anthropic import ChatAnthropic
from langchain.schema.runnable.config import RunnableConfig
from langchain.schema import StrOutputParser
from langchain.prompts import ChatPromptTemplate

# Set ANTHROPIC_API_KEY

literal_client = LiteralClient(api_key="lsk-***")

cb = literal_client.langchain_callback()

prompt = ChatPromptTemplate.from_messages(
    ['human', 'Tell me a short joke about {topic}']
)

model = ChatAnthropic(model_name="claude-3-5-sonnet-20240620")
runnable = prompt | model

res = runnable.invoke(
    {"topic": "ice cream"},
    config=RunnableConfig(callbacks=[cb], run_name="joke")
)

[desaxce]

It works with ChatAnthropic(model_name="claude-3-5-sonnet-20240620", streaming=True) too.

[kumar781]

will it work with azureopenai gpt 4o?