Add handling for account tiles for specific account type.

- List individual account instead of account type under User & account
  screen.

- Add handling to move account tiles with specific account type from
  top level account dashboard to inside the corresponding account
  preference.

- Rename settings.accounts.AccountPreference to
  settings.accounts.AccountTypePreference to make it less confused
  with settings.AccountPreference

Bug: 31801423
Test: make RunSettingsRoboTests
Change-Id: Iebe70a3c4230e8d979344f142a5c2a60945e552e