Make UserManager#DISALLOW_OEM_UNLOCK a system API.

This is needed for unbundling of OobConfig app.

Test: gts-tradefed run gts -m GtsGmscoreHostTestCases --test com.google.android.gts.devicepolicy.DeviceOwnerUserRestrictionTest#testDisallowOemUnlock_canSetWithSystemApi
Test: gts-tradefed run gts -m GtsGmscoreHostTestCases --test com.google.android.gts.devicepolicy.DeviceOwnerUserRestrictionTest#testDisallowOemUnlock_doCannotSet

BUG: 32974379

Change-Id: I7710df96006821a5d0eddfe0b411dd3efa0e10f0
2 files changed