A new error message is a good thing, it means you have made some progress! 
It appears that your RStudio IDE and rsconnect are properly publishing the app and indicating that it has Python content, but Python is not installed on the RStudio Connect server, which in this case is the QuickStart VM.
You could install Python from source per the RStudio Connect admin guide, or...
If you downloaded the QuickStart more than a week or so ago, we actually published a new version of the QuickStart VM that has Python 3.7 already installed and a few sample apps with Python content already deployed.
So, you can re-download the latest version of the QuickStart VM from https://www.rstudio.com/products/quickstart/, start it up, and then you should be able to deploy your Python content to RStudio Connect.