Do not show warnings for unhandled messages

Summary: Flipper receives a lot of messages which cannot be handled when plugins unbundled. Showing them as warnings is un-actionable with such big amount, so I disabled them.

Reviewed By: mweststrate

Differential Revision: D25557790

fbshipit-source-id: 1a0bc3df2848b194b72ea6d775ffabe416672fee

desktop/app/src/Client.tsx

@@ -487,7 +487,7 @@ export default class Client extends EventEmitter {
               }
             }
           }
-          if (!handled) {
+          if (!handled && !isProduction()) {
             console.warn(`Unhandled message ${params.api}.${params.method}`);
           }
         }