The /streaming/ part of the URL... That's indicative of something being placed into temporary storage for the specific purpose of being sent to the user. So it's not really permanent and thus shouldn't be attempted to be referenced manually.
Usually a link is displayed when embedded interactive preview is incompatible with the device/browser combination.
From what I understand, using the "Insert File" script step instead of the "Insert PDF" script step can also cause the link (instead of the preview) to be displayed sometime.
Sorry to reply this so late. So how to make mobile browser incompatible with the preview ?