feat: pass in response body (#1203)

Author: SkArchon

v2/pkg/engine/resolve/loader.go

@@ -55,10 +55,16 @@ type ResponseInfo struct {
 	Request *http.Request
 	// ResponseHeaders contains a clone of the headers of the response from the subgraph.
 	ResponseHeaders http.Header
+	// ResponseBody contains the response body of the subgraph, it is of type string so that it cannot be manipulated.
+	ResponseBody string
 }
 
 func newResponseInfo(res *result, subgraphError error) *ResponseInfo {
-	responseInfo := &ResponseInfo{StatusCode: res.statusCode, Err: goerrors.Join(res.err, subgraphError)}
+	responseInfo := &ResponseInfo{
+		StatusCode:   res.statusCode,
+		Err:          goerrors.Join(res.err, subgraphError),
+		ResponseBody: res.out.String(),
+	}
 	if res.httpResponseContext != nil {
 		// We're using the response.Request here, because the body will be nil (since the response was read) and won't
 		// cause a memory leak.