accounts/keystore: fix flaky test (#21703)

* accounts/keystore: add timeout to test to prevent failure on travis

The TestWalletNotifications test sporadically fails on travis.
This is because we shutdown the event collection before all events are received.
Adding a small timeout (10 milliseconds) allows the collector to be scheduled
and to consume all pending events before we shut it down.

* accounts/keystore: added newlines back in

* accounts/keystore: properly fix the walletNotifications test