Make it clear we are working with a partnerToken and fix bug where we updated a conversation to the senderKey and not the partnerKey

'Fix' the msg update failure in DMs. This is almost certainly causing an upsert failure when sending messages but it replicates channels behavior. Will mark in a ticket to fix later.

Update to use event model changes that add the senderKey in addition to the partnerPubKey on the callbacks

Move the codeset from conversation to each message, since they change over time and can be different between users