Fix canvas connection point z-indexing bug (#107223)

fix(canvas): hoist connect points one level higher in DOM to fix z-index

public/app/features/canvas/runtime/root.tsx

@@ -54,6 +54,7 @@ export class RootElement extends FrameState {
         {this.elements.map((v) => (
           <Fragment key={v.UID}>{v.render()}</Fragment>
         ))}
+        {this.scene.connections.render()}
       </div>
     );
   }

public/app/features/canvas/runtime/scene.tsx

@@ -366,7 +366,6 @@ export class Scene {
 
     const sceneDiv = (
       <>
-        {this.connections.render()}
         {this.root.render()}
         {this.isEditingEnabled && (
           <Portal>

public/app/plugins/panel/canvas/components/connections/ConnectionAnchors.tsx

@@ -137,7 +137,6 @@ const getStyles = (theme: GrafanaTheme2) => ({
     cursor: 'cursor',
     width: `calc(5px + 2 * ${ANCHOR_PADDING}px)`,
     height: `calc(5px + 2 * ${ANCHOR_PADDING}px)`,
-    zIndex: 100,
   }),
   highlightElement: css({
     backgroundColor: '#00ff00',