Fixes#4262
When using non-native providers like Groq with models that require LiteLLM,
the error message was confusing: 'LiteLLM is not available, falling back to LiteLLM'.
This commit:
- Fixes the contradictory error message
- Provides a clear, actionable error message that includes:
- The model name that requires LiteLLM
- Instructions on how to install LiteLLM (pip install 'crewai[litellm]')
- Adds tests to verify the error message is helpful and includes the model name
Co-Authored-By: João <joao@crewai.com>
f084a3514a