Record is duplicated when client receives response with removed phantom id and existing id

[bmblb]

Reported by client.

In responsive systems it is possible for a client to send two requests for one added record and backend can respond with two responses both of which will contain $PhantomId.

Use case:

1. User creates a record
2. Sync request sent out immediately
3. User changes the name of the added record
4. Backend haven't responded yet with an id, so record.isPhantom is true and sync request is sent with the added record once again.
5. Backend creates id for the new record and sends first response with PhantomId/id pair
6. Backend receives 2nd request, updates existing record and sends the response with the same PhantomId/id pair
7. User receives 1st response, replaces phantomid with id
8. User receives 2nd response with PhantomId, cannot find one (even though id exists) and adds that record as new

Arguably it is responsibility of the backend to remove PhantomId field from the 2nd response. However, there is a logic in place already which splits added array into added/updated, we need to extend it to handle existing id too.