Merge pull request #9743 from IgniteUI/vmihalkov/fix-9632

Allow IgxForOf directive input to be null

Author: ChronosSF

projects/igniteui-angular/src/lib/directives/for-of/for_of.directive.ts

@@ -92,7 +92,7 @@ export class IgxForOfDirective<T> implements OnInit, OnChanges, DoCheck, OnDestr
      * ```
      */
     @Input()
-    public igxForOf: any[];
+    public igxForOf: any[] | null;
 
     /**
      * An @Input property that sets the property name from which to read the size in the data object.