Exposes user type related hidden APIs in UserManager.

UserManager#isAdminUser, UserManager#isPrimaryUser,
UserManager#isGuestUser, and UserManager#isRestrictedProfile
are now exposed as System APIs for SUW. All of them require the
MANAGE_USERS permission.

Bug: 115270753
Test: manual (run setup wizard)
Change-Id: I5b9685d486738c3d5a7f5cfa6748adb6efef91bb