Bump langchain-openai from 0.3.12 to 0.3.15

Bumps [langchain-openai](https://github.com/langchain-ai/langchain) from 0.3.12 to 0.3.15.
- [Release notes](https://github.com/langchain-ai/langchain/releases)
- [Commits](langchain-ai/langchain@langchain-openai==0.3.12...langchain-openai==0.3.15)

---
updated-dependencies:
- dependency-name: langchain-openai
  dependency-version: 0.3.15
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

requirements.txt

@@ -1,5 +1,5 @@
 langchain-couchbase==0.2.4
-langchain-openai==0.3.12
+langchain-openai==0.3.15
 pandas==2.2.3
 python-dotenv==1.1.0
 streamlit==1.44.1