get_bedrock_anthropic_callback does not return token values correctly

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_aws import ChatBedrock
from langchain_community.callbacks.manager import get_bedrock_anthropic_callback

llm = ChatBedrock(model_id="anthropic.claude-3-haiku-20240307-v1:0")
# llm = ChatBedrock(model_id="anthropic.claude-v2")

with get_bedrock_anthropic_callback() as cb:
    result = llm.invoke("Tell me a joke")
    result2 = llm.invoke("Tell me a joke")
    print(cb)

Error Message and Stack Trace (if applicable)

This is not an error, but rather the actual behavior. As shown on the referenced page -> Tracking token usage.

Tokens Used: 0
    Prompt Tokens: 0
    Completion Tokens: 0
Successful Requests: 2
Total Cost (USD): $0.0

Description

Description: I encountered an issue with the get_bedrock_anthropic_callback function in Langchain. According to the documentation, the function should provide token usage details, but it returns all token values as 0.

Steps to Reproduce:

Use get_bedrock_anthropic_callback as described in the documentation. Observe that token values are returned as 0. Expected Behavior: The function should return the correct token usage values.

Actual Behavior: The function returns all token values as 0.

Considering the use of Claude 3 Opus, it would be beneficial to include Opus (anthropic.claude-3-opus-20240229-v1:0) in the model cost mapping. Here are the current values for reference:

langchain_community.callbacks.bedrock_anthropic_callback

MODEL_COST_PER_1K_INPUT_TOKENS = {
    "anthropic.claude-instant-v1": 0.0008,
    "anthropic.claude-v2": 0.008,
    "anthropic.claude-v2:1": 0.008,
    "anthropic.claude-3-opus-20240229-v1:0": 0.015,
    "anthropic.claude-3-sonnet-20240229-v1:0": 0.003,
    "anthropic.claude-3-haiku-20240307-v1:0": 0.00025,
}

MODEL_COST_PER_1K_OUTPUT_TOKENS = {
    "anthropic.claude-instant-v1": 0.0024,
    "anthropic.claude-v2": 0.024,
    "anthropic.claude-v2:1": 0.024,
    "anthropic.claude-3-opus-20240229-v1:0": 0.075,
    "anthropic.claude-3-sonnet-20240229-v1:0": 0.015,
    "anthropic.claude-3-haiku-20240307-v1:0": 0.00125,
}

System Info

Langchain: langchain==0.2.0rc2 langchain-anthropic==0.1.12 langchain-aws==0.1.3 langchain-chroma==0.1.0 langchain-community==0.2.0rc1 langchain-core==0.1.52 langchain-openai==0.1.6 langchain-text-splitters==0.0.1

OS: windows10

Python: 3.10.4

langchain-ai / langchain