build(deps): bump langsmith in the uv group across 1 directory

Bumps the uv group with 1 update in the / directory: [langsmith](https://github.com/langchain-ai/langsmith-sdk).


Updates `langsmith` from 0.7.26 to 0.8.18
- [Release notes](https://github.com/langchain-ai/langsmith-sdk/releases)
- [Commits](langchain-ai/langsmith-sdk@v0.7.26...v0.8.18)

---
updated-dependencies:
- dependency-name: langsmith
  dependency-version: 0.8.18
  dependency-type: indirect
  dependency-group: uv
...

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

Author: dependabot[bot]