Bump pydantic-settings from 2.8.1 to 2.9.1 (#1188)

Bumps [pydantic-settings](https://github.com/pydantic/pydantic-settings) from 2.8.1 to 2.9.1.
- [Release notes](https://github.com/pydantic/pydantic-settings/releases)
- [Commits](pydantic/pydantic-settings@v2.8.1...v2.9.1)

---
updated-dependencies:
- dependency-name: pydantic-settings
  dependency-version: 2.9.1
  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]

pyproject.toml

@@ -107,7 +107,7 @@ strict = [
     "mp-api==0.45.4",
     "numpy",
     "phonopy==2.30.1",
-    "pydantic-settings==2.8.1",
+    "pydantic-settings==2.9.1",
     "pydantic==2.11.3",
     "pymatgen-analysis-defects==2025.1.18",
     "pymatgen==2025.2.18",