Allow the supervision component requirement for...

Allow the supervision component requirement for DPM#setSecondaryLockscreenEnabled to be bypassed for testOnly admins.

This allows for CTS test coverage of the API.

Bug: 155120891
Test: atest FrameworksServicesTests:DevicePolicyManagerTest
Test: atest -c 'CtsDevicePolicyManagerTestCases:com.android.cts.devicepolicy.MixedProfileOwnerTest#testSecondaryLockscreen'
Change-Id: Ife0ede63bf7dc10f082451ea0b32ce01f14f97fc