chore(deps-dev): update ruff requirement from >=0.8 to >=0.15.12 in /sdk

Updates the requirements on [ruff](https://github.com/astral-sh/ruff) to permit the latest version.
- [Release notes](https://github.com/astral-sh/ruff/releases)
- [Changelog](https://github.com/astral-sh/ruff/blob/main/CHANGELOG.md)
- [Commits](astral-sh/ruff@0.8.0...0.15.12)

---
updated-dependencies:
- dependency-name: ruff
  dependency-version: 0.15.12
  dependency-type: direct:development
...

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

Author: dependabot[bot]

sdk/pyproject.toml

@@ -34,7 +34,7 @@ dev = [
     "pytest-asyncio>=1.3.0",
     "mypy>=1.14",
     "mypy-protobuf>=3.6",
-    "ruff>=0.8",
+    "ruff>=0.15.12",
     "grpcio-tools>=1.68.0",
 ]