feat(query-builder): export directive

Author: igdmdimitrov

projects/igniteui-angular/src/lib/query-builder/public_api.ts

@@ -6,6 +6,7 @@ export {
     IgxQueryBuilderComponent
 } from './query-builder.component';
 export * from './query-builder-header.component';
+export * from './query-builder.directives';
 
 /* NOTE: Query builder directives collection for ease-of-use import in standalone components scenario */
 export const IGX_QUERY_BUILDER_DIRECTIVES = [

projects/igniteui-angular/src/lib/query-builder/query-builder-tree.component.html

@@ -249,7 +249,7 @@ <h6 class="igx-filter-empty__title">
             <ng-container 
                 *ngTemplateOutlet="
                     searchValueTemplate ? searchValueTemplate : defaultSearchValueTemplate;
-                    context: { $implicit: _editedExpression.expression.searchVal, field: selectedField, condition: selectedCondition }
+                    context: { $implicit: searchValue, field: selectedField, condition: selectedCondition }
                 "
             >
             </ng-container>