refactor(frontend): 非ログイン画面でのmeta取得を減らす (#13776)

* refactor(frontend): 非ログイン画面でのmeta取得を減らす

* fix(frontend): サーバー供給のmetaとクライアントフォールバックで取れるmetaの型が違うのを修正

* force fetch meta at welcome.vue

* refactor

packages/frontend/src/components/MkFeaturedPhotos.vue

@@ -4,19 +4,11 @@ SPDX-License-Identifier: AGPL-3.0-only
 -->
 
 <template>
-<div v-if="meta" :class="$style.root" :style="{ backgroundImage: `url(${ meta.backgroundImageUrl })` }"></div>
+<div v-if="instance" :class="$style.root" :style="{ backgroundImage: `url(${ instance.backgroundImageUrl })` }"></div>
 </template>
 
 <script lang="ts" setup>
-import { ref } from 'vue';
-import * as Misskey from 'misskey-js';
-import { misskeyApi } from '@/scripts/misskey-api.js';
-
-const meta = ref<Misskey.entities.MetaResponse>();
-
-misskeyApi('meta', { detail: true }).then(gotMeta => {
-	meta.value = gotMeta;
-});
+import { instance } from '@/instance.js';
 </script>
 
 <style lang="scss" module>