Add handling of admin enforced restrictions in Users Settings

Before, when the restrictions were applied, the preferences that were restricted were hidden.

After this change, if admin applies a restriction, the preference is displayed as disabled and Policy Transparency Dialog is displayed

Bug: 338226475
Test: atest UserSettingsTest && atest UserDetailsSettingsTest
Flag: android.multiuser.new_multiuser_settings_ux
Change-Id: I1b5aeeeec7accde278ff3e46ea3d64c91d8400db