test(slider): run the whole suite of tests

Closes #5762

Author: Aleksandyr

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

@@ -13,7 +13,7 @@ const SLIDER_CLASS = '.igx-slider';
 const THUMB_TO_CLASS = '.igx-slider__thumb-to';
 const THUMB_FROM_CLASS = '.igx-slider__thumb-from';
 
-fdescribe('IgxSlider', () => {
+describe('IgxSlider', () => {
     configureTestSuite();
     beforeEach(async(() => {
         TestBed.configureTestingModule({