next.js

f2cf3dc8 - [next-server] skip setting vary header for basic routes (#77797)

[next-server] skip setting vary header for basic routes (#77797) ### What After https://github.com/vercel/vercel/pull/13011 landed on Vercel CLI, noticing that we're still checking the `vary` header in the tests, which is obselete now. In this PR we delete the handling for setting the `vary` header but still keep the cases of interception routes since it's still needed. ### Why Since v13.4.6 we added the `_rsc` query with the unique hash, `vary` header becomes not required anymore. Closes NDX-1010