it fixes the issue Are you sure convert:true parameter did not work? I got your code working for me. Everything is the same as you have above, except 'convert':'true' and Authorization header was added.
seems to work fine By the recent Google's update, the property of exportLinks was also added to Drive API v3. This property had been able to be used at only Drive API v2 before. By this update, the URLs for exporting the converted files of Google Docs can be retrieved using the files.get method of Drive API v3. The endpoint for this method is as follows. Endpoint: