Use system default icons for phone account UI.

Add assets and assign phone account icons 1-4 in order. PhoneAccounts
are re-registered every time there is a change in the state of the phone
accounts (e.g. add and remove a single account) so reassigning the icons
will ensure they are always consistent (in consecutive order).

Bug: 16685783

Change-Id: I51e0f3465077a207b751843d97708e5f7b86c89c
21 files changed