next.js

e7a8645c - BREAKING CHANGE: remove deprecated analyticsId from config, and the corresponding performance-relayer files and tests (#64199)

BREAKING CHANGE: remove deprecated analyticsId from config, and the corresponding performance-relayer files and tests (#64199) ### 🤔 What's in there? We've deprecated config's `analyticsId` in 14.1.1 [almost 3 months ago](https://github.com/vercel/next.js/releases/tag/v14.1.1-canary.2). Users can opt in fot `@vercel/speed-insights`, or use `useReportWebVitals` to report to any provider they'd like. This PR: - removes `analyticsId` key from configuration - stops setting `__NEXT_PUBLIC_ANALYTICS_ID` env variable when the key was present - stops injecting `performance-relayer` file, when the variable is set - cleans up related test code.