Replace Anthropic LLM with ChatAnthropic

[JasonWeill]

Description

Running a %%ai magic command with the anthropic model provider, such as the following:

%%ai anthropic:claude-v1.2
Write a poem about C++.

… yields a warning: (split across two lines for readability)

…lib/python3.11/site-packages/langchain/llms/anthropic.py:140:
UserWarning: This Anthropic LLM is deprecated. Please use `from langchain.chat_models import ChatAnthropic` instead

The prompt continues to run.

Reproduce

1. Run the prompt listed above.
2. See the warning above the output.

Expected behavior

The Jupyter AI invokes the ChatAnthropic LLM provider, not the deprecated Anthropic model provider.

Context

• Operating System and version: macOS 12.6.6 "Monterey"
• Browser and version: Firefox ESR
• JupyterLab version: 4.0.3, with Jupyter AI 2.0.0

Troubleshoot Output

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You may want to sanitize the paths in the output.

Command Line Output

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Browser Output

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