refactor: typing component template refs for VModal (#5994)

#### What type of PR is this?

/area ui
/kind improvement
/milestone 2.16.x

#### What this PR does / why we need it:

为 VModal 组件的引用添加类型。

See https://vuejs.org/guide/typescript/composition-api.html#typing-component-template-refs

#### Does this PR introduce a user-facing change?

```release-note
None
```

ui/console-src/modules/interface/menus/components/MenuItemEditingModal.vue

@@ -28,7 +28,7 @@ const emit = defineEmits<{
 
 const { t } = useI18n();
 
-const modal = ref();
+const modal = ref<InstanceType<typeof VModal> | null>(null);
 const selectedParentMenuItem = ref<string>("");
 const formState = ref<MenuItem>({
   spec: {
@@ -121,7 +121,7 @@ const handleSaveMenuItem = async () => {
       emit("saved", data);
     }
 
-    modal.value.close();
+    modal.value?.close();
 
     Toast.success(t("core.common.toast.save_success"));
   } catch (e) {
@@ -381,7 +381,7 @@ onMounted(() => {
           @submit="$formkit.submit('menuitem-form')"
         >
         </SubmitButton>
-        <VButton @click="modal.close()">
+        <VButton @click="modal?.close()">
           {{ $t("core.common.buttons.cancel_and_shortcut") }}
         </VButton>
       </VSpace>