Migrate lock task policy APIs to coexistence

Bug: 258442693
Bug: 232918480
Test: atest android.devicepolicy.cts.LockTaskTest with flag
enabled/disabled
Change-Id: Ib8d4498ce84db42ad409adc807f20ad25beb3ace

Change-Id: Idb1d2d277f35850c6e24134dcbeb83c3c0001aa1
8 files changed