refactor(product-list): 优化 SKU 展示逻辑

- 将 SKU、SKU2 和 SKU3 的展示合并到一个条件判断中- 优化 SKU 复制按钮的布局和样式
- 添加无 SKU 时的提示符

src/views/product-manage/product-list/component/DataTableSlot.vue

@@ -53,20 +53,25 @@ function handleMonitor() {
       <ProductInfo :displayCompetitor="true" :img-width="60" :item="row" />
     </div>
     <div v-else-if="field === 'sku'" style="color: #1d2129;">
-      <div class="flex items-center justify-center max-h-5">
-        {{ row.sku ? row.sku : '-' }}
-        <el-button v-if="row.sku" :icon="CopyDocument" class="ml-1 cursor-pointer" link @click="handleCopy(row.sku || '')">
-        </el-button>
-      </div>
-      <div v-if="row.sku2" class="flex items-center justify-center max-h-5">
-        {{ row.sku2 ? row.sku2 : '-' }}
-        <el-button v-if="row.sku2" :icon="CopyDocument" class="ml-1 cursor-pointer" link @click="handleCopy(row.sku2 || '')">
-        </el-button>
+      <div v-if="row.sku || row.sku2 || row.sku3" class="flex items-center justify-center max-h-5">
+        <div v-if="row.sku">
+          {{ row.sku }}
+          <el-button :icon="CopyDocument" class="ml-1 cursor-pointer" link
+                     @click="handleCopy(row.sku || '')"></el-button>
+        </div>
+        <div v-if="row.sku2">
+          {{ row.sku2 }}
+          <el-button :icon="CopyDocument" class="ml-1 cursor-pointer" link
+                     @click="handleCopy(row.sku2 || '')"></el-button>
+        </div>
+        <div v-if="row.sku3">
+          {{ row.sku3 }}
+          <el-button :icon="CopyDocument" class="ml-1 cursor-pointer" link
+                     @click="handleCopy(row.sku3 || '')"></el-button>
+        </div>
       </div>
-      <div v-if="row.sku3" class="flex items-center justify-center max-h-5">
-        {{ row.sku3 ? row.sku3 : '-' }}
-        <el-button v-if="row.sku3" :icon="CopyDocument" class="ml-1 cursor-pointer" link @click="handleCopy(row.sku3 || '')">
-        </el-button>
+      <div v-else>
+        -
       </div>
     </div>
     <div v-else-if="field === 'country_code'">