refactor(web-ele): 移除未使用的工具函数

- 删除了 utils/index.ts 中未使用的树处理和类型判断函数
- 更新了相关文件中的导入路径
- 优化了代码结构，提高了代码的可读性和维护性

apps/web-ele/src/views/mall/product/spu/components/info-form.vue

@@ -1,6 +1,6 @@
 <script lang="ts" setup>
 import { useVbenForm } from '#/adapter/form';
-import { handleTree } from '#/utils';
+import { handleTree } from '@vben/utils';
 import * as ProductCategoryApi from '#/api/mall/product/category';
 import * as ProductBrandApi from '#/api/mall/product/brand';
 import { watch } from 'vue';

apps/web-ele/src/views/mall/product/spu/components/sku-list.vue

@@ -226,11 +226,10 @@
 </template>
 <script lang="ts" setup>
 import { copyValueToTarget } from '#/utils';
-import { formatToFraction } from '@vben/utils';
+import { formatToFraction, isEmpty } from '@vben/utils';
 import type { PropertyAndValues, RuleConfig } from './model';
 import UploadImg from '#/components/upload/image-upload.vue';
 import { ElTable, ElInput, ElMessage } from 'element-plus';
-import { isEmpty } from '#/utils/is';
 import type { MallSpuApi } from '#/api/mall/product/spu';
 import { ref, watch } from 'vue';
 import type { PropType } from 'vue';