Bump langsmith in /ai/gen-ai-agents/travel-agent/files

Bumps [langsmith](https://github.com/langchain-ai/langsmith-sdk) from 0.3.42 to 0.7.31.
- [Release notes](https://github.com/langchain-ai/langsmith-sdk/releases)
- [Commits](langchain-ai/langsmith-sdk@v0.3.42...v0.7.31)

---
updated-dependencies:
- dependency-name: langsmith
  dependency-version: 0.7.31
  dependency-type: direct:production
...

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

Author: dependabot[bot]

ai/gen-ai-agents/travel-agent/files/requirements.txt

@@ -80,7 +80,7 @@ langgraph==0.4.5
 langgraph-checkpoint==3.0.0
 langgraph-prebuilt==0.1.8
 langgraph-sdk==0.1.69
-langsmith==0.3.42
+langsmith==0.7.31
 MarkupSafe==3.0.2
 marshmallow==3.26.2
 matplotlib==3.10.3