Bump langchain-core from 0.2.13 to 0.2.16

Bumps [langchain-core](https://github.com/langchain-ai/langchain) from 0.2.13 to 0.2.16.
- [Release notes](https://github.com/langchain-ai/langchain/releases)
- [Commits](langchain-ai/langchain@langchain-core==0.2.13...langchain-core==0.2.16)

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

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

Author: dependabot[bot]

poetry.lock

@@ -69,7 +69,7 @@ pydantic = "^2.7.3"
 pydantic_core = "^2.18.4"
 langchain = "^0.2.1"
 langchain-community = "^0.2.1"
-langchain-core = "^0.2.13"
+langchain-core = "^0.2.16"
 langchain-openai = "^0.1.14"
 unstructured = "^0.14.4"
 Markdown = "^3.6"