PLT-4233 When internet reconnects, reconnect websocket and grab latest posts, etc. (#4500)

* When internet reconnects, reconnect websocket and grab latest posts, etc.

* Rename internet connection variable

webapp/client/client.jsx

@@ -156,6 +156,10 @@ export default class Client {
         // NO-OP for inherited classes to override
     }
 
+    handleSuccess(res) { // eslint-disable-line no-unused-vars
+        // NO-OP for inherited classes to override
+    }
+
     handleResponse(methodName, successCallback, errorCallback, err, res) {
         if (res && res.header) {
             this.serverVersion = res.header[HEADER_X_VERSION_ID];
@@ -212,6 +216,7 @@ export default class Client {
                 console.error('Missing response body for ' + methodName); // eslint-disable-line no-console
                 successCallback('', res);
             }
+            this.handleSuccess(res);
         }
     }