Minimize the number of default enabled IMEs part 2

Previously the system tried to enable at least one auxiliary IME
even when the system is not ready.  However, this doesn't make
much sense because the user should be able to set up their phone
without auxiliary IMEs. Also, IMEs enabled before the system
becomes ready are kept to be enabled after the system becomes
ready. Thus, we should minimize the number of enabled IMEs
until the system becomes ready.

BUG: 17347871
Change-Id: Ife93d909fb8a24471c425c903e2b7048826e17a3