Also update the account preferences in displayPreference().

- start creating the account preferences in displayPreference() to make
the data available earlier.
- when trying to update the UI when the page is resumed, instead of
clearing the whole list and add the latest accounts, compare the
differences between the currently shown accounts and the latest accounts
and only update the account preferences that has been changed.

Change-Id: I249eb2fe67f4adaab02bf77680c62d07756dc94a
Fix: 34035653
Test: make RunSettingsRoboTests