How to reproduce:
- Log in at Wikimedia Commons with an account not belonging to a user group having the upload_by_url user right.
- Navigate to Special:UploadWizard
- Press "Share images from Flickr".
- Select and describe the images and proceed to the publish step.
- Try to publish. It fails with Unknown error: "permissiondenied".
- Button ("Share images from Flickr") not visible to users without necessary permission.
This issue is causing confusion and is a regression, therefore I classify it as high priority.