ERROR ITMS-90471: "Missing Image Asset. Your app is missing the Large App Icon asset 'AppIconSmall' in 'Payload/YourApp.app' is thrown when uploading an TVOS project to the app store. This is likely due to the extension of the image for TVOS
Package any tvos build for distribution and upload it to tvos, the upload process should continue without any error or warning.
Head over to the existingAnswerHub thread and let us know what's up.