fix(grid): add sorting for state persistance sample

Author: Svetloslav15

src/app/grid/grid-state-persistence-sample/grid-state-persistance-sample.component.html

@@ -14,7 +14,7 @@
 </div>
 
 <div class="grid__wrapper">
-    <igx-grid [igxPreventDocumentScroll]="true" [igxGridState]="options"  #grid
+    <igx-grid [igxPreventDocumentScroll]="true" [igxGridState]="options"  #grid [sortStrategy]="customStrategy"
         [data]="data | async" [height]="'500px'" width="100%" [autoGenerate]='false' [allowFiltering]="true">
         <igx-column [field]="'Category'" [sortable]="true" [width]="'120px'"></igx-column>
         <igx-column [field]="'Type'" [sortable]="true" [width]="'150px'" [filterable]='false'></igx-column>

src/app/grid/grid-state-persistence-sample/grid-state-persistance-sample.component.ts

@@ -17,7 +17,7 @@ export class GridStatePersistenceSampleComponent {
     public grid: IgxGridComponent;
     @ViewChild(IgxGridStateDirective, { static: true })
     public state!: IgxGridStateDirective;
-    
+    public customStrategy = NoopSortingStrategy.instance();
     public data: Observable<any[]>;
     public options: IGridStateOptions = {
         rowSelection: true,