Bump langchain-openai from 0.1.14 to 0.1.15

Bumps [langchain-openai](https://github.com/langchain-ai/langchain) from 0.1.14 to 0.1.15.
- [Release notes](https://github.com/langchain-ai/langchain/releases)
- [Commits](langchain-ai/langchain@langchain-openai==0.1.14...langchain-openai==0.1.15)

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

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

pyproject.toml

@@ -70,7 +70,7 @@ pydantic_core = "^2.18.4"
 langchain = "^0.2.1"
 langchain-community = "^0.2.1"
 langchain-core = "^0.2.16"
-langchain-openai = "^0.1.14"
+langchain-openai = "^0.1.15"
 unstructured = "^0.14.4"
 Markdown = "^3.6"
 faiss-cpu = "^1.8.0"