Update revalidate handling for app (#49062)
This updates revalidate handling for app and moves some exports from
`next/server` to `next/cache`
x-ref: [slack
thread](https://vercel.slack.com/archives/C042LHPJ1NX/p1682535961644979?thread_ts=1682368724.384619&cid=C042LHPJ1NX)
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