Bump langchain-text-splitters

Bumps [langchain-text-splitters](https://github.com/langchain-ai/langchain) from 0.3.5 to 0.3.9.
- [Release notes](https://github.com/langchain-ai/langchain/releases)
- [Commits](langchain-ai/langchain@langchain-text-splitters==0.3.5...langchain-text-splitters==0.3.9)

---
updated-dependencies:
- dependency-name: langchain-text-splitters
  dependency-version: 0.3.9
  dependency-type: direct:production
...

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

Author: dependabot[bot]

ai/gen-ai-agents/assistant-secretary-agent/files/local_requirements.txt

@@ -36,7 +36,7 @@ langchain==0.3.14
 langchain-community==0.3.14
 langchain-core==0.3.29
 langchain-experimental==0.3.4
-langchain-text-splitters==0.3.5
+langchain-text-splitters==0.3.9
 langgraph==0.2.62
 langgraph-checkpoint==2.0.8
 langgraph-sdk==0.1.51