[devicemanager]

HKLM\Software\Microsoft\Inbox\Settings SMSNoSentMsg = 0
HKCU\ControlPanel\Notifications\Default Options = 0
HKCU\Software\Microsoft\Inbox\Settings DisableSMSDeliveryReceipt = 0

That will get rid of the notification, but will still make the SMS icon show in the top tool bar, but will go away. You will get no popup.