Edge decorator is misplaced when going cross-hierarchy with child area offsets

[NiklasRentzCAU]

In this graph the edge arrow head will be misplaced by the exact 25,25 child area offset, as if it was applied twice for that.

Example see this .kgt:

knode misplacedDecorator {
    properties: org.eclipse.elk.hierarchyHandling = INCLUDE_CHILDREN
    krectangle {
        styles: background=255r,255g,255b
        kchildArea {
            areaData:topLeftAnchor=left 25, top 25
        }
    }
    knode src {
        knode inSource3 {
            size: width=50 height=50
            krectangle
        }
        krectangle 
        kedge (-> inSource3) // The arrow head decorator is offset too much by the 25,25 of the child area.
    }
}

[NiklasRentzCAU]

This does not occur in KIELER.

[NiklasRentzCAU]

Fixed by 2019452 in KLighD.