fix(routing): don't access Request headers (#12498)

Co-authored-by: ascorbic <[email protected]>

Author: ematipico

.changeset/unlucky-kids-compete.md

@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Fixes a regression where Astro was trying to access `Request.headers`

packages/astro/src/core/middleware/noop-middleware.ts

@@ -1,7 +1,8 @@
 import type { MiddlewareHandler } from '../../@types/astro.js';
 import { NOOP_MIDDLEWARE_HEADER } from '../constants.js';
 
-export const NOOP_MIDDLEWARE_FN: MiddlewareHandler = (ctx, next) => {
-	ctx.request.headers.set(NOOP_MIDDLEWARE_HEADER, 'true');
-	return next();
+export const NOOP_MIDDLEWARE_FN: MiddlewareHandler = async (_ctx, next) => {
+	const response = await next();
+	response.headers.set(NOOP_MIDDLEWARE_HEADER, 'true');
+	return response;
 };