Bump langchain in /community/llm-prompt-design-helper

Bumps [langchain](https://github.com/langchain-ai/langchain) from 0.2.6 to 0.3.30.
- [Release notes](https://github.com/langchain-ai/langchain/releases)
- [Commits](langchain-ai/langchain@langchain==0.2.6...langchain==0.3.30)

---
updated-dependencies:
- dependency-name: langchain
  dependency-version: 0.3.30
  dependency-type: direct:production
...

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

Author: dependabot[bot]

community/llm-prompt-design-helper/requirements.txt

@@ -1,7 +1,7 @@
 gradio==4.43.0
 openai==1.35.4
 langchain-nvidia-ai-endpoints
-langchain==0.2.6
+langchain==0.3.30
 langchain-community
 langchain-openai
 wget