chore(deps): Bump langchain from 1.2.12 to 1.3.1

Bumps [langchain](https://github.com/langchain-ai/langchain) from 1.2.12 to 1.3.1.
- [Release notes](https://github.com/langchain-ai/langchain/releases)
- [Commits](langchain-ai/langchain@langchain==1.2.12...langchain==1.3.1)

---
updated-dependencies:
- dependency-name: langchain
  dependency-version: 1.3.1
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]