fix(tabs): Fix for applying styles to tabs group #4351 (#4371)

Author: sboykova

projects/igniteui-angular/src/lib/tabs/tabs-group.component.ts

@@ -71,10 +71,8 @@ export class IgxTabsGroupComponent implements IgxTabsGroupBase, AfterContentInit
     /**
      * @hidden
      */
-    @HostBinding('class')
-    get styleClass(): string {
-        return 'igx-tabs__group';
-    }
+    @HostBinding('class.igx-tabs__group')
+    public styleClass = true;
 
     @HostListener('window:resize', ['$event'])
     public onResize(event) {