Refactoring: introduce UserLogoutInteractor

Change code to use Flows for detecting possibility of Logout, and
introduce UserLogoutInteractor that would handle logout-specific
scenarios.

This change in a preparation step for adding desktop-style logout
functionality.

Bug: 375384623
Bug: 206032495
Flag: EXEMPT Mechanical refactoring
Test: atest UserLogoutInteractorTest
Test: atest UserRepositoryImplTest
Test: atest KeyguardIndicationControllerBaseTest
Test: atest GlobalActionsDialogLiteTest
Test: atest KeyguardUpdateMonitorTest
Change-Id: Ib54a6530176bcd937ad9005be6da675ad06d41e6