fix(pivotGrid): Set sort index on afterViewInit in case header is rendered after already sorted on load/expand.

Author: skrustev

projects/igniteui-angular/src/lib/grids/pivot-grid/pivot-row-dimension-header.component.ts

@@ -1,4 +1,4 @@
-import { ChangeDetectionStrategy, ChangeDetectorRef, Component, ElementRef, HostListener, Inject } from '@angular/core';
+import { AfterViewInit, ChangeDetectionStrategy, ChangeDetectorRef, Component, ElementRef, HostListener, Inject } from '@angular/core';
 
 import { GridType, IGX_GRID_BASE, PivotGridType } from '../common/grid.interface';
 
@@ -22,7 +22,7 @@ import { PivotUtil } from './pivot-util';
     standalone: true,
     imports: [IgxIconComponent, NgTemplateOutlet, NgIf, NgClass, SortingIndexPipe]
 })
-export class IgxPivotRowDimensionHeaderComponent extends IgxGridHeaderComponent {
+export class IgxPivotRowDimensionHeaderComponent extends IgxGridHeaderComponent implements AfterViewInit {
     private pivotGrid: PivotGridType;
 
     constructor(
@@ -39,6 +39,10 @@ export class IgxPivotRowDimensionHeaderComponent extends IgxGridHeaderComponent
             .subscribe((_: ISortingExpression[]) => this.setSortIndex());
     }
 
+    public ngAfterViewInit(): void {
+        this.setSortIndex();
+    }
+
     @HostListener('click', ['$event'])
     public override onClick(event: MouseEvent) {
         event.preventDefault();