How to get generated texture of sprite atlas in editor from script?

I would like to assign my atlas texture to a material texture for my Graphics.DrawMeshInstancedIndirect to use in the editor, but I can’t find a texture that is not generated at runtime?

This works for getting the texture of an atlas from editor script or !runtime by using any sprite packed in it.

SpriteUtility.GetSpriteTexture(sprites[0], true);