This was a holdover from Signal's origins as a pure SMS app.
It causes problems, depends on undefined device specific behavior,
and should no longer be necessary now that we have all the
information we need to E164 all numbers.
// FREEBIE
1) Migrate from GSON to Jackson everywhere.
2) Add support for storing identity key conflicts on message rows.
3) Add limited support for surfacing identity key conflicts in UI.
