Initialize ContactsUnavailableFragment in onAttachFragment

- This block of code was removed by mistake in ag/1452346.
- Here's the original history of the block:
  - ag/57051, ag/80412, ag/120732, ag/483115.

Bug: 31633212
Bug: 30944495

Test: manual
  - follow steps to repro in b/31633212.
  - follow steps in ag/1452346.

Change-Id: I90c60abd900e0edb2f941339fdb0fee3a3e7d9e5