JSON.Stringify identity value in the auth test
JSON.Stringify identity value in the auth test

- Change is just to be at parity with the .NET test code

shrishrirang/azure-mobile-apps-node,mamaso/azure-mobile-apps-node,mamaso/azure-mobile-apps-node,shrishrirang/azure-mobile-apps-node,mamaso/azure-mobile-apps-node,shrishrirang/azure-mobile-apps-node