CI: Fix issue with conflicting 'engines.pnpm' field in next-stats-action (#92533)
This job has been failing on canary pushes, but not on PRs. I'm not sure why it's only happening in canary pushes, but hopefully this should fix the specific error we're seeing when it does fail.
Discussion: https://vercel.slack.com/archives/C04KC8A53T7/p1775571376147179