docs: scope whole-route dynamic rendering claim for cookies to the previous model (#100811)
## Summary
The production checklist and the `cookies` API reference said
request-time APIs opt the entire route into dynamic rendering, which
contradicts the Cache Components caching guide (reading `cookies()`
inside `<Suspense>` streams only that subtree). Both pages now lead with
the Cache Components behavior and scope the whole-route claim to
"Without Cache Components".
- `production-checklist.mdx`: rewrite the Request-time APIs bullet to
point at Suspense and the caching guide; remove the outdated "Partial
Prerendering (experimental)" Good to know.
- `cookies.mdx`: split the whole-route sentence into a "Without Cache
Components" bullet and note that only the Suspense subtree streams with
Cache Components.
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