[FLINK-39017][web] Fix task click handler in job graph for Chrome 144+

Chrome 144 introduced BoundaryEventDispatchTracksNodeRemoval which
changes how pointer/mouse boundary events are dispatched after DOM
mutations. The onNodeMouseEnter handler used appendChild to reorder
SVG elements for z-ordering, which caused Chrome to reset the logical
pointer target to the parent graph element. This prevented click
events from reaching the node-group elements.

Remove appendChild DOM mutations from onNodeMouseEnter and
onNodeMouseLeave. Link focus styling on hover is preserved via
property changes without DOM reordering.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
(cherry picked from commit f5e7558)

Author: MartijnVisser

flink-runtime-web/web-dashboard/src/app/components/dagre/dagre.component.ts

@@ -360,7 +360,6 @@ export class DagreComponent extends NzGraph {
    * @param $event
    */
   onNodeMouseEnter($event: MouseEvent): void {
-    this.graphElement.nativeElement.appendChild($event.target);
     this.layoutLinks.forEach(l => {
       if (l.id.split('-').indexOf(($event.target as HTMLElement).id) !== -1) {
         l.options.focused = true;
@@ -377,20 +376,6 @@ export class DagreComponent extends NzGraph {
       l.options.focused = this.focusedLinkIds.indexOf(l.id) !== -1;
     });
 
-    this.graphElement.nativeElement.appendChild(this.overlayElement.nativeElement);
-
-    this.graphElement.nativeElement.querySelectorAll(`.link-group`).forEach((e: Element) => {
-      if (this.focusedLinkIds.indexOf(e.id) !== -1) {
-        this.graphElement.nativeElement.appendChild(e);
-      }
-    });
-
-    this.graphElement.nativeElement.querySelectorAll(`.node-group`).forEach((e: Element) => {
-      if ([this.selectedNodeId, ...this.circleNodeIds].indexOf(e.id) !== -1) {
-        this.graphElement.nativeElement.appendChild(e);
-      }
-    });
-
     this.cd.detectChanges();
   }