Revert "Use CP2 for default account setting in AOSP."

This reverts commit e17434d5.

Reason for revert: Remove the default account settings from AOSP Contacts App, since there is a system setting for default account in Android Baklava

Bug: 399801558
Tested: atest ContactsTests CtsProviderTestCases CtsContactsProviderTestCases GtsContactsProviderHostCases GtsContactsTest
Flag: EXEMPTED



Change-Id: I686066d2cb99b7ab6cf8b05e3beebb51e0900d36