Exposed some DPM members as @TestApi.

Test: m update-api devicepolicy-deviceside-common
Test: atest \
      CtsDevicePolicyManagerTestCases:DeviceOwnerTest#testDevicePolicySafetyCheckerIntegration \
      CtsDevicePolicyManagerTestCases:ProfileOwnerTest#testDevicePolicySafetyCheckerIntegration

Bug: 172376923

Change-Id: I7dbcf357404dcfe030f3206d3a222315c7c164af
4 files changed