Select the checkbox beside the option 'Share iTunes Library XML with other applications'. On the pop-up window, go to the 'Advanced' tab.
Open iTunes > Click 'File' menu > 'Edit' > 'Preferences' to open the iTunes Preferences window. Please follow the steps to import iTunes library to Spotify. That's to say, you are able to add iTunes playlist to Spotify from your local computer. But it still keeps the option to upload local files to Spotify via the 'Add A Source'. Spotify has removed the top menu to import playlist from iTunes. How to Import iTunes Playlist to Spotify Manually