This is not possible. Your ASDK subscription and portal is almost completely independant of your Azure Subscription, You will not be able to manage them both on one portal. This is also not possible in a full installation of Azure Stack Hub.
If you would like to move a VM on-prem in the ASDK and move it to your Azure Subscription, you will need to move it manually by uploading the .vhd to Azure. Azure Storage Explorer or AzCopy will be helpful in this move.