[UE] Allow the ability to use DA-based images in Universal Editor

As an author I would like to be able to drag an image into UE like I can on DA so that I can create content easily.

Start by locating the Universal Editor image-insertion entry point and comparing it with DA’s existing image-drag behavior. Confirm how a DA-based image is represented and define done as dragging it into UE creating usable content; the issue names no files or tests, so the implementation path needs clarification first.

Written by the indexing model from the issue text.