Fix accessibility label strings for profiles

This change adds a user type details property to specify
accessibility label for a profile and exposes it from a hidden
UserManager API. We also use this API to get the accessibility label
strings for profiles in PhoneStatusBarPolicy and other places within the
framework.

Bug: 329551064
Test: atest UserManagerTest. Also, tested manually by flashing the
changes locally and setting up private space.

Flag: ACONFIG android.multiuser.enable_private_space_features NEXTFOOD

Change-Id: Icaf26c17de32aaf63b985d69dd6902b1112a4a75