Set dirty to ensure disconnection circle updates

Moving the draw operation to the background means that the distance
check logic was no longer being tracked. since only a single bg draw was
made.

This is slightly less than ideal, but it's reasonable to expect that the
user will continually be dragging the mouse when moving links

src/lib/litegraph/src/LGraphCanvas.ts

@@ -5015,6 +5015,7 @@ export class LGraphCanvas implements CustomEventDispatcher<LGraphCanvasEventMap>
           }
         )
       }
+      if (renderLink instanceof MovingInputLink) this.setDirty(false, true)
 
       ctx.fillStyle = colour
       ctx.beginPath()