Flickering when preview processor finishes processing image

When looking at an image content profile page for which preview processing hasn't finished yet, we will show the image as is. However, when preview processing finishes, the page receives a push notification for this and will try to refresh the preview. However, as the image is already there, this results in the image appearing to flicker.

When looking at an image, we can just ignore the preview processor finished push notification.

See https://github.com/oaeproject/3akai-ux/pull/3703