Bump langchain-classic in /ai/langchain-skills-agent/src

Bumps [langchain-classic](https://github.com/langchain-ai/langchain) from 1.0.2 to 1.0.7.
- [Release notes](https://github.com/langchain-ai/langchain/releases)
- [Commits](langchain-ai/langchain@langchain-classic==1.0.2...langchain-classic==1.0.7)

---
updated-dependencies:
- dependency-name: langchain-classic
  dependency-version: 1.0.7
  dependency-type: indirect
...

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Author: dependabot[bot]