Alerting/testing promql extraction (#34665)

* promql compat for marshaling

* extracts upstream instant queries into data frame for alerting

* eval string parity

pkg/services/ngalert/api/api_testing.go

@@ -74,7 +74,7 @@ func (srv TestingApiSrv) RouteTestRuleConfig(c *models.ReqContext, body apimodel
 		http.MethodGet,
 		queryURL,
 		nil,
-		jsonExtractor(nil),
+		instantQueryResultsExtractor,
 		nil,
 	)
 }