Added reject with new Error if OpenVidu fetch fails because of network problems.

openvidu-node-client/src/OpenVidu.ts

@@ -483,9 +483,11 @@ export class OpenVidu {
             // `error.request` is an instance of XMLHttpRequest in the browser and an instance of
             // http.ClientRequest in node.js
             console.error(error.request);
+            reject(new Error(error.request));
           } else {
             // Something happened in setting up the request that triggered an Error
             console.error('Error', error.message);
+            reject(new Error(error.message));
           }
         });
     });