Set langchain version for crewai example

[sfc-gh-chu]

Description

Resets langchain versions in trulens-apps-langchain and defines constraints in the CrewAI example

Other details good to know for developers

Please include any other details of this change useful for TruLens developers.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to
  not work as expected)
• New Tests
• This change includes re-generated golden test results
• This change requires a documentation update

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Important

Set specific langchain and langchain-core version constraints for CrewAI example and trulens-apps-langchain.

• Dependencies:
  • Update langchain to ">=0.3.9" and langchain-core to ">=0.3.21" in examples/expositional/frameworks/crewai/surprise_trip/pyproject.toml.
  • Downgrade langchain to ">=0.2.10" and langchain-core to ">=0.2.0" in src/apps/langchain/pyproject.toml.

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