Remove default Device Owner restrictions

As part of the work to deprecate Corporate-Owned Managed Profile (COMP)
mode, remove the restrictions that are set by default when a Device
Owner is set on the device.

The Device Owner used to be able to add/remove the restrictions for
adding/removing a managed profile.

In the new mode, this restriction will be set by default, by the system,
and not removeable by the device owner.

Test: atest FrameworksServicesTests:DevicePolicyManagerTest
Test: atest CtsDevicePolicyManagerTestCases:com.android.cts.devicepolicy.DeviceOwnerPlusProfileOwnerTest
Bug: 143517714
Bug: 138709492
Change-Id: Ice5f8b678327b2c901623cc8f4dd6d60271b361b