chore(*): Add detectChanges to test.

Author: MKirova

projects/igniteui-angular/src/lib/splitter/splitter.component.spec.ts

@@ -343,6 +343,7 @@ describe('IgxSplitter pane toggle', () => {
         fixture = TestBed.createComponent(SplitterTogglePaneComponent);
         fixture.detectChanges();
         splitter = fixture.componentInstance.splitter;
+        fixture.detectChanges();
     }));
 
     it('should collapse/expand panes', () => {