Allow some packages to be excluded during during work profile creation.

Bug: 31657192
Test: adb shell am instrument -e class com.android.server.pm.UserManagerTest#testAddManagedProfile_withDisallowedPackages -w com.android.frameworks.servicestests/android.support.test.runner.AndroidJUnitRunner
Change-Id: I37eab6084e0f911d0e2407186b789875588194a2