Hi! Not sure i understand, you dont need any kind of licensing permission to upload the APK to the store. P.S. i would really suggest using the APK maker app if you dont want to mess up with Android Studio.
Ok, license control is much more than just providing a license code there, it requires proper checks on both the content pack and on the Kustom app itself, i would suggest you opening a feature request in this site and ask to implement that