Make master clear constants system APIs.

This is needed for unbundling of the OobConfig apk.

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

Bug: 32974361

Change-Id: I71e7270bb4c3234ec0516382b18a2ca35aab4c81