Fix "Welcome back Guest" dialog dismisses when screen turns off.

New constructor to SystemUIDialog has been introduced which does not take theme (apply default) and takes additional boolean parameter dismissOnDeviceLock. This has been used with false.

Bug: 199768843
Test: atest SystemUIDialogTest
Change-Id: Ib423a58ad9efe557a8ee5c95807026a6c0fa5f93