[ci] Update sizebot node_modules caching strategy

The download job for sizebot requires both modules from the root repo
but also has a nested yarn lockfile in scripts/release. Calculate the
hash for the cache using both lockfiles.

ghstack-source-id: fc1703b547ab906ee244cfa3540414a6df8c660e
Pull Request resolved: https://github.com/facebook/react/pull/30393