I created a free account to try out Adbobe Stock and I did the same thing by accident. Instead of placing the images in the library, I have licensed them all. While searching Google to undo this is stumbled on this support item.
Branching to a new discussion,Hi Marc,Sorry to hear that.Since you have accidentally licensed Adobe Stock files(10), I have added 10 image licenses to your account so that you can use them against different images.Also, please refer to Stock FAQ: How to license an image with Adobe Stock? in order to license an image in Adobe Stock correctly.Hope this helps!Feel free to update this thread in case of any additional questions.Regards,Twarita