chore(deps): bump langchain-core in /generative_ai/understand_docs (GoogleCloudPlatform#13245)

Bumps [langchain-core](https://github.com/langchain-ai/langchain) from 0.2.33 to 0.2.43.
- [Release notes](https://github.com/langchain-ai/langchain/releases)
- [Commits](langchain-ai/langchain@langchain-core==0.2.33...langchain-core==0.2.43)

---
updated-dependencies:
- dependency-name: langchain-core
  dependency-type: direct:production
...

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

Author: dependabot[bot]

generative_ai/understand_docs/requirements.txt

@@ -7,7 +7,7 @@ google-cloud-aiplatform[all]==1.69.0
 sentencepiece==0.2.0
 google-auth==2.38.0
 anthropic[vertex]==0.28.0
-langchain-core==0.2.33
+langchain-core==0.2.43
 langchain-google-vertexai==1.0.10
 numpy<2
 openai==1.30.5