Rename get/setProtectedPackages methods

Based on API council feedback that current method names are ambiguous,
renaming them with
setUserControlDisabledPackages/getUserControlDisabledPackages.

Bug: 150865604
Test: atest DevicePolicyManagerTest
atest com.android.cts.devicepolicy.DeviceOwnerTest#testSetUserControlDisabledPackages

Change-Id: I74f07ae5f0e9b425a6f2e4aa52d2cb8ac42da68e