[postcreate] properly set is_instance_of for bootstrap entities
Entities created before CWEType itself need the is/is_instance_of
relations created later. We were actually only inserting "is".
Closes #7656606.
sync_schema_props_perms('cwuri')
helper = repo.system_source.dbhelper
cu = session.cnxset.cu
helper.set_null_allowed(cu, 'moved_entities', 'extid', 'VARCHAR(256)', False)
commit()