Offline ImportContacts request

[vkryl]

There're user reports saying that you can rename contacts without connection on other mobile clients, but you can't in TDLib.

I can't confirm if it works properly in Android client after connection is restored or application being restarted, but probably, like with messages, TDLib could save contact name & send corresponding updateUser/updateChatTitle immediately, then apply it on server asynchronously (in case contact was not modified from other client in between).

[levlam]

Yes, it can be done, but with two remarks:

1. We can't reliably detect, whether a contact was modified from other client, so it will be changed server-side anyway.
2. The name change will be rolled back to the previous, if the server request is unsuccessful.