Change registration process

[barrydegraaff]

Can the registration process be moved to after the first send as long as first send is not using largmail API, or at least after the send mention pop-up appears. The rationale is the user can see more of the product or experience more, before being asked to register. This may improve free-to-pay adoption. If this can be done, moving it later in the process, please see if you can do this in now or in a future update.