Dialer: Don't show the same number twice

* There was already an attempt to hide duplicates but it operated on
  the basis that the results were exactly the same
* In reality I get to choose the main number twice since it's somehow
  returned with and without spaces
* Normalizing the numbers resolves that

Change-Id: Iff89a668f0473e99cf4660927b495f7c5bfb1dfb