Add new Lock Task feature to enable Quick Settings.

This should only be settable by the system supervision app.

Bug: 401577081
Bug: 373403206
Test:  atest FrameworksServicesTests:DevicePolicyManagerTest and local
build.
Flag: android.app.supervision.flags.enable_lock_task_feature_quick_settings

Change-Id: I956fc5d989846e12260ac60b82ca369f0d7d7583