CloudWatch: Refactor tests, remove unused parameters (#48815)

pkg/tsdb/cloudwatch/response_parser.go

@@ -64,7 +64,7 @@ func aggregateResponse(getMetricDataOutputs []*cloudwatch.GetMetricDataOutput) m
 			id := *r.Id
 			label := *r.Label
 
-			response := newQueryRowResponse(id)
+			response := newQueryRowResponse()
 			if _, exists := responseByID[id]; exists {
 				response = responseByID[id]
 			}