Fix apparently invalid auto-test (qmlwebsockets)

It makes sense to first start listening (server.listen = true) and then
connect (socket.active = true).

Task-number: QTBUG-59388
Change-Id: I4235dad87ee3a62ebf75cec39e5d9fa4b7ed7552
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>