fix onBeforeResponse (#2053)

Author: huseeiin

.changeset/eager-wings-crash.md

@@ -0,0 +1,5 @@
+---
+"@solidjs/start": minor
+---
+
+fix onBeforeResponse

packages/start/src/middleware/index.ts

@@ -36,7 +36,7 @@ function wrapResponseMiddleware(onBeforeResponse: ResponseMiddleware): Middlewar
 
     const fetchEvent = getFetchEvent(h3Event);
     const mwResponse = await onBeforeResponse(fetchEvent, {
-      body: (resp as any)?.body,
+      body: resp,
     });
     if (mwResponse) return mwResponse;
   };