planner: cache mpp info to avoid frequent grpc calling - #65694

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: bazel-contrib/setup-bazel@8310a45e30297e76bc8fbae427fb6068efa01eb8. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/