Add visibility for new location of permission apex.

This is prep. work for f/b/apex/permission migraton to
packages/modules/Permission.  The Build System does not
enforce location checks within visibility, which allows
us to add the new location post migration and ensure
migration process does not run into visibility related errors.

BUG: 167963264
Test: TH
Change-Id: I765b73bb8e0f377ef03805423807e720f1e90582