perf[DragSelect]: add $listeners

src/components/DragSelect/index.vue

 <template>
-  <el-select ref="dragSelect" v-model="selectVal" v-bind="$attrs" class="drag-select" multiple>
+  <el-select ref="dragSelect" v-model="selectVal" v-bind="$attrs" class="drag-select" multiple v-on="$listeners">
     <slot/>
   </el-select>
 </template>