chore(deps): Bump langchain from 0.3.15 to 0.3.19 (#562)

* chore(deps): Bump langchain from 0.3.15 to 0.3.19

Bumps [langchain](https://github.com/langchain-ai/langchainjs) from 0.3.15 to 0.3.19.
- [Release notes](https://github.com/langchain-ai/langchainjs/releases)
- [Changelog](https://github.com/langchain-ai/langchainjs/blob/main/release_workspace.js)
- [Commits](langchain-ai/langchainjs@0.3.15...0.3.19)

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

Signed-off-by: dependabot[bot] <[email protected]>

* chore: update pnpm-lock.yaml

---------

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: cloud-sdk-js <[email protected]>

Author: dependabot[bot]