Refactor UserInteractor to UserSwitcherInteractor

This change aims at splitting up access to selected user data into a
smaller interactor such that there are fewer dependencies as there are
many classes that depend on just getting the current user info

Test: ran all sysui tests
Bug: b/303808405
Change-Id: I197fdf33a04419eb819c4b46fcf470080d01aa26
24 files changed