build(deps): bump pydantic from 2.11.9 to 2.12.0 in /clients/python (kubeflow#1738)

Bumps [pydantic](https://github.com/pydantic/pydantic) from 2.11.9 to 2.12.0.
- [Release notes](https://github.com/pydantic/pydantic/releases)
- [Changelog](https://github.com/pydantic/pydantic/blob/main/HISTORY.md)
- [Commits](pydantic/pydantic@v2.11.9...v2.12.0)

---
updated-dependencies:
- dependency-name: pydantic
  dependency-version: 2.12.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]