test(hierarchical-grid-navigation): add additional await in the test

Author: georgianastasov

projects/igniteui-angular/src/lib/grids/hierarchical-grid/hierarchical-grid.navigation.spec.ts

@@ -666,6 +666,8 @@ describe('IgxHierarchicalGrid Navigation', () => {
             hierarchicalGrid.verticalScrollContainer.getScroll().scrollTop = 2000;
             fixture.detectChanges();
             await wait(DEBOUNCE_TIME);
+            fixture.detectChanges();
+            await wait(DEBOUNCE_TIME);
 
             const hierarchicalGridRect = hierarchicalGrid.tbody.nativeElement.getBoundingClientRect();
             const lastRowRect = hierarchicalGrid.dataRowList.last.nativeElement.getBoundingClientRect();