Remove flagging from existing Device Policy APIs

Early in the Android V release, permission annotations were
added to getEnrollmentSpecificId() and getPendingSystemUpdate(),
both of which are existing public APIs. These changes were
erroneously flagged, causing them to disappear from the beta
release. Fix this by removing the flagging.

Bug: 331121264
Test: builds
Change-Id: Ia2ed00e9075a53fe543902b5706ee22e29ffd0d4