Doing sublisting after deduplication

For message like "a@anrdoid.com b@android.com", we wanna show no
suggestion on them because it will be ambiguous (Two chips with
label "Send Email"). And this is achieve by deduplication.

Previously, we did sublisting before duplication, and thus
we failed to remove some duplications. Let's do it the another way round.

BUG: 130344529

Test: atest
Change-Id: Idb4ea439daca710ce6247611f97c657e6a1c1a1b