[DO NOT MERGE] While-list apps to access account if already saw it

Sync adapters without an account access cannot run until the
user approves the account access (for the case the account
access is not allowed by other policy such as being singed
with the same cert as the authenticator). However, if the
sync adapter package already got the account from another
app which means it already saw the account we white-list
the sync adapter app to access the account as it already
saw it - the bird is out of the cage.

bug:31162498

Change-Id: I2b72f3b0d6307561ed68db2f2e9c900b15e8d098