Add integration tests for Anthropic/Cohere/Groq/Litellm/Mistral/AI21

[devin-ai-integration]

Changes

• Added pytest.skip() for missing API keys in test files
• Standardized API key handling across all provider tests
• Fixed docstring formatting in test files
• Improved test pattern descriptions

Known Issues (Need Resolution)

1. Package Version/Compatibility Issues:

   • Mistral: Missing 'Chat' class in mistralai package
   • AI21: Missing module 'ai21.clients.studio.resources.studio_answer'
   • These suggest incompatible or outdated package versions

2. Environment Configuration Issues:

   • Python 3.7, 3.8, and 3.9 interpreters missing in CI environment
   • Preventing tests from running on these Python versions

3. Test Implementation Issues:

   • LiteLLM: Maximum recursion depth exceeded in time travel cache
   • This needs investigation in the test implementation

Link to Devin run: https://app.devin.ai/sessions/9301617f90e843e0aa0e665551a08ab4

[devin-ai-integration]

🤖 Devin AI Engineer

I'll be helping with this pull request! Here's what you should know:

✅ I will automatically:

• Address comments on this PR. Add "(aside)" to your comment to have me ignore it.
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[areibman]

Will fix this on a separate branch. Devin was a bad intern :(