[release-2.0] fix: activated theme not loaded after initialization (#793)

This is an automated cherry-pick of #790

/assign ruibaby

```release-note
修复首次初始化之后，Console 没有加载已激活主题的问题。
```

src/views/system/Setup.vue

@@ -18,6 +18,7 @@ import type {
   SinglePageRequest,
   Tag,
 } from "@halo-dev/api-client";
+import { useThemeStore } from "@/stores/theme";
 
 const router = useRouter();
 
@@ -98,6 +99,8 @@ const handleSubmit = async () => {
 
     const systemStateStore = useSystemStatesStore();
     await systemStateStore.fetchSystemStates();
+    const themeStore = useThemeStore();
+    await themeStore.fetchActivatedTheme();
 
     router.push({ name: "Dashboard" });
   } catch (error) {