Improve WebSocketServer Error Handling (#6230)

* Improve WebSocketServer Error Handling

Closes: https://github.com/parse-community/parse-server/issues/6173

Prevents an unhandled server rejection.

Includes an example for LiveQuery test and closing the proper connections.

Improve live query monitoring

* fix tests

src/LiveQuery/ParseLiveQueryServer.js

@@ -392,6 +392,8 @@ class ParseLiveQueryServer {
         event: 'ws_disconnect',
         clients: this.clients.size,
         subscriptions: this.subscriptions.size,
+        useMasterKey: client.hasMasterKey,
+        installationId: client.installationId,
       });
     });
 

src/LiveQuery/ParseWebSocketServer.js

@@ -23,6 +23,9 @@ export class ParseWebSocketServer {
         }
       }, config.websocketTimeout || 10 * 1000);
     };
+    wss.onError = error => {
+      logger.error(error);
+    };
     wss.start();
     this.server = wss;
   }