Add DPMI methods for setting and clearing local restrictions from a

system entity EnforcingAdmin.

Also update existing method for clearing a Role-based EnforcingAdmin's
policies to take a list of admin packages instead of just 1.

Bug: 383624414
Flag: android.app.supervision.flags.supervision_manager_apis
Test: atest SupervisionServiceTest
Change-Id: I3daf12ee9eaebd28b187a6ff03b7134127010f34