Fix phone account preference removal in telephony.

Additionally add/maintain following behavior changes:
For multi-SIM devices:
  - Always show the account list (even if only SIM-based accounts)
  - Always list the SIM accounts
For single-SIM devices
  - If there are no 3rd party (3P) accounts, do not show the account
    list nor any options (make-calls-with, enable-accounts-list)
  - If there are only disabled 3P accounts, show the "enable accounts"
    preference but do not list any accounts (including SIM)
  - If there is at least one enabled 3P account display all options
    and list all accounts, including SIM-based accounts.

Bug: 20303449
Change-Id: I0d36a2fab0abea01853003ef60cce48cf4f1f6c6
2 files changed