fix(grid): properly account for custom row edit buttons, #7049

Author: ViktorSlavov

projects/igniteui-angular/src/lib/grids/grid-base.directive.ts

@@ -2003,7 +2003,7 @@ export class IgxGridBaseDirective extends DisplayDensityBase implements
     /**
      * @hidden @internal
      */
-    @ContentChildren(IgxRowEditTabStopDirective)
+    @ContentChildren(IgxRowEditTabStopDirective, { descendants: true })
     public rowEditTabsCUSTOM: QueryList<IgxRowEditTabStopDirective>;
 
     /**