fix: ensure nodelink vis always appears centered in the view

During a demo by Michael he noticed the node link vis did not appear centered. I didn't notice due to my screen having a pixel density of 1, but the offset needs to take that pixel density into account. Simple fix :)

libs/shared/lib/vis/visualizations/nodelinkvis/components/NLPixi.tsx

@@ -812,8 +812,8 @@ export const NLPixi = forwardRef((props: Props, refExternal) => {
 
       let stopped = 0;
 
-      const widthHalf = app.renderer.width / 2;
-      const heightHalf = app.renderer.height / 2;
+      const widthHalf = app.renderer.width / (2 * window.devicePixelRatio);
+      const heightHalf = app.renderer.height / (2 * window.devicePixelRatio);
       graph.current.nodes.forEach((node, i) => {
         if (!layoutAlgorithm.current) return;
         const gfx = nodeMap.current.get(node._id);