Add a wait to ensure zone stable callback has time to resolve.

Author: MKirova

projects/igniteui-angular/src/lib/grids/grid/grid-filtering-ui.spec.ts

@@ -3860,6 +3860,7 @@ describe('IgxGrid - Filtering actions - Excel style filtering #grid', () => {
             scrollbar.scrollTop = displayContainer.getBoundingClientRect().height / 2;
             await wait(200);
             fix.detectChanges();
+            await wait(100);
 
             // Type string in search box
             const inputNativeElement = GridFunctions.getExcelStyleSearchComponentInput(fix, searchComponent);