locksettings: clean up references to managed profiles

Clean up some code (comments, method names, class names) in
LockSettingsService that referred to managed profiles (or work profiles,
which are the same thing as managed profiles), when they really meant
any profile with unified challenge.  Originally only managed profiles
supported unified challenge, so this code was fine originally.  But now
"clone profiles" support unified challenge too.  There's also a plan to
add another profile type that supports unified challenge.

Bug: 214355283
Test: atest com.android.server.locksettings
Flag: exempt, mechanical refactoring
Change-Id: Ica472482983de13a19fcd9da966273e8d2e974ad