Added some additional error handlers to get a better grip on connection issues

Summary: I think it is good to have error handlers where-ever possible, so that there is historical data in our monitoring when we need it, and can track from which point of the code it originates :)

Reviewed By: jknoxville

Differential Revision: D21040059

fbshipit-source-id: 1c07fbfa65379739554bc98f83761ae97870ba82

desktop/app/src/Client.tsx

@@ -174,6 +174,9 @@ export default class Client extends EventEmitter {
         onSubscribe(subscription) {
           subscription.request(Number.MAX_SAFE_INTEGER);
         },
+        onError(payload) {
+          console.error('[client] connection status error ', payload);
+        },
       });
     }
   }