Addressing https://phab.comm.dev/D13963#inline-78590 and https://phab.comm.dev/D13963#inline-78595.
Right now we have the same approach each time:
1. Sending device list updates to all our peers
2. Sending device list updates to all our devices that are on the device list, but without the primary device
3. Call `getAndUpdateDeviceListsForUsers` for our `userID`
** update `AuxUserStore*
** get platform details if the device was added
Depends on D13963