Delay showing the controls ui after dialog

In the case that the user clicks Yes on the dialog to change the
setting, onComplete should be called after the keyguard is either
dismissed (and the setting is changed) or canceled. That way, the
correct value of the setting will be sent to the app.

Test: atest ControlsSettingsDialogManagerImplTest
Test: manual using mock app
Fixes: 270913547
Change-Id: I5aae816c457e932e24d4b83ad66549d8b22e0b5b