SearchFragment removes stale data from the database

When search fragment is created, it will get a list of
the non-indexable keys and verify that each of the results
are not a part of that list.

This CL moves the non-indexable keys logic into a
controller for shared use between SearchFragment
and DatabaseIndexingManager.

Bug:33209418
Test: make RunSettingsRoboTests
Change-Id: I4ed3812ecc5ee9e63b75ba6edbc7ff8712e8e9c9