submit pubkey when a user is adding a new private key from the settings

>    What about Settings -> Keys -> Import Private Key when the user wants to add a new one key?

Good question. Haven't thought about it. You can skip this one until I think about it more. For now I'm mainly concerned about using the right key during account setup.

_Originally posted by @tomholub in https://github.com/FlowCrypt/flowcrypt-android/issues/767#issuecomment-552448758_