Bug 1064156 - Add unit test for bug 824131 - Wifi wrong password notific...

...ation
An unit test ensures the function being tested works as expected. For `_updateNetworkStatus`, we should only test `wifiContext.forgetNetwork` and `wifiContext._wifiWrongPassword` are called with correct parameters. `assert.isTrue(fakeCb.called)` is more like an integration test and I would suggest to place it in a separate file.