Fix: Unresolved param in x-nextjs-rewritten-query (#81991)
Fixes an issue with the x-nextjs-rewritten-query header where it
responded without the dynamic parts of the URL filled in.
For example, when rewriting to `/hello?id=123` to `/hello/123`:
- Before: `x-nextjs-rewritten-query: id=__ESC_COLON_id`
- After: `x-nextjs-rewritten-query: id=123`
