Bump langchain-core from 0.3.76 to 0.3.81 (#7185)

Bumps [langchain-core](https://github.com/langchain-ai/langchain) from 0.3.76 to 0.3.81.
- [Release notes](https://github.com/langchain-ai/langchain/releases)
- [Commits](langchain-ai/langchain@langchain-core==0.3.76...langchain-core==0.3.81)

---
updated-dependencies:
- dependency-name: langchain-core
  dependency-version: 0.3.81
  dependency-type: indirect
...

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

Author: dependabot[bot]