Revalidate cache in statistic API

[mazipan]

Is your feature request related to a problem? Please describe.
Next.js will automatically cache the fetch in the server, we already set the cache key/tag for the statistics API. But never have a revalidation.

Ideally, we need to revalidate after new user is registered successfully.

And every new questions submitted.

Describe the solution you'd like

https://nextjs.org/docs/app/building-your-application/data-fetching/fetching-caching-and-revalidating#revalidating-data