Update list header only when contacts in default directory are loaded

* We don't need to consider non-default directory when updating main view
  and account view anyway.

* The bug doesn't always manifest because:
  - It takes some extra time for non-default directory contacts to be loaded.
https://cs.corp.google.com/android/packages/apps/ContactsCommon/src/com/android/contacts/common/list/ContactEntryListFragment.java?l=393
  - The contacts in non-default directory may be empty.

Bug 30792969

Change-Id: I7b02af3012cdcf815165986daeb61efb3c5c70b1