chore(deps): Bump langchain from 0.2.15 to 0.2.16

Bumps [langchain](https://github.com/langchain-ai/langchain) from 0.2.15 to 0.2.16.
- [Release notes](https://github.com/langchain-ai/langchain/releases)
- [Commits](langchain-ai/langchain@langchain==0.2.15...langchain==0.2.16)

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

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

pyproject.toml

@@ -67,7 +67,7 @@ sentry-sdk = "^2.13.0"
 bitcash = "^1.0.2"
 pydantic = "^2.7.3"
 pydantic_core = "^2.18.4"
-langchain = "^0.2.15"
+langchain = "^0.2.16"
 langchain-community = "^0.2.15"
 langchain-core = "^0.2.38"
 langchain-openai = "^0.1.23"