fix: submenu type lose theme

Author: tangjinzhou

components/menu/demo/sider-current.vue

@@ -50,18 +50,18 @@ function getItem(
 }
 
 const items: ItemType[] = reactive([
-  getItem('Navigation One', 'sub1', h(MailOutlined), [
+  getItem('Navigation One', 'sub1', () => h(MailOutlined), [
     getItem('Option 1', '1'),
     getItem('Option 2', '2'),
     getItem('Option 3', '3'),
     getItem('Option 4', '4'),
   ]),
-  getItem('Navigation Two', 'sub2', h(AppstoreOutlined), [
+  getItem('Navigation Two', 'sub2', () => h(AppstoreOutlined), [
     getItem('Option 5', '5'),
     getItem('Option 6', '6'),
     getItem('Submenu', 'sub3', null, [getItem('Option 7', '7'), getItem('Option 8', '8')]),
   ]),
-  getItem('Navigation Three', 'sub4', h(SettingOutlined), [
+  getItem('Navigation Three', 'sub4', () => h(SettingOutlined), [
     getItem('Option 9', '9'),
     getItem('Option 10', '10'),
     getItem('Option 11', '11'),

components/menu/demo/submenu-theme.vue

@@ -66,7 +66,7 @@ const items: ComputedRef<MenuProps['items']> = computed(() => [
   getItem(
     'Navigation One',
     'sub1',
-    h(MailOutlined),
+    () => h(MailOutlined),
     [getItem('Option 1', '1'), getItem('Option 2', '2'), getItem('Option 3', '3')],
     theme.value,
   ),

components/menu/src/interface.ts

@@ -16,7 +16,7 @@ export interface SubMenuType extends ItemSharedProps {
   disabled?: boolean;
 
   key: string;
-
+  theme?: MenuTheme;
   rootClassName?: string;
 
   // >>>>> Icon