fix(graphql): add timeout to _resolveQueryOnNetwork

Author: ykuc7

packages/graphql/lib/src/core/query_manager.dart

@@ -244,7 +244,8 @@ class QueryManager {
 
     try {
       // execute the request through the provided link(s)
-      response = await link.request(request).first;
+      response =
+          await link.request(request).timeout(Duration(seconds: 5)).first;
 
       queryResult = mapFetchResultToQueryResult(
         response,