fix(igx-ts-legacy): fi grid type import and add missing override

Author: Hristo313

packages/igx-templates/igx-ts-legacy/hierarchical-grid/hierarchical-grid-batch-editing/files/src/app/__path__/__filePrefix__.component.ts

@@ -1,7 +1,6 @@
 import { Component, ViewChild } from '@angular/core';
 import { IgxDialogComponent, IgxGridComponent, IgxHierarchicalGridComponent,
-  IgxRowIslandComponent, Transaction } from '<%=igxPackage%>';
-import { GridType } from '<%=igxPackage%>/lib/grids/common/grid.interface';
+  IgxRowIslandComponent, GridType, Transaction } from '<%=igxPackage%>';
 
 import { SINGERS } from './data';
 import { Singer } from './singer';

packages/igx-templates/igx-ts-legacy/hierarchical-grid/hierarchical-grid-summaries/files/src/app/__path__/custom-summary.ts

@@ -5,7 +5,7 @@ export class CustomSummary extends IgxNumberSummaryOperand {
     super();
   }
 
-  public operate(data?: number[]): IgxSummaryResult[] {
+  public override operate(data?: number[]): IgxSummaryResult[] {
     const result: IgxSummaryResult[] = [];
     if (!data) {
       return result;