chore(*): Update scroll throttle multiplier for multi cell selection tests.

Author: MKirova

projects/igniteui-angular/grids/tree-grid/src/tree-grid-multi-cell-selection.spec.ts

@@ -34,7 +34,7 @@ describe('IgxTreeGrid - Multi Cell selection #tGrid', () => {
 
         beforeEach(() => {
             TestBed.configureTestingModule({
-                providers: [{ provide: SCROLL_THROTTLE_TIME_MULTIPLIER, useValue: 1 }]
+                providers: [{ provide: SCROLL_THROTTLE_TIME_MULTIPLIER, useValue: 0 }]
             });
             fix = TestBed.createComponent(IgxTreeGridSelectionKeyComponent);
             fix.detectChanges();