Ensure chained middleware rewrites work properly (#46866)
Follow-up to https://github.com/vercel/next.js/pull/45772 this ensures
the rewrite header can be correctly set when a chained middleware
rewrite is occurring.
x-ref: [slack
thread](https://vercel.slack.com/archives/C01RGMANU9Y/p1678074803731489)
## Bug
- [x] Related issues linked using `fixes #number`
- [x] Integration tests added
- [ ] Errors have a helpful link attached, see
[`contributing.md`](https://github.com/vercel/next.js/blob/canary/contributing.md)
