perf(frontend): use css-native implementation for spacer rather than vue component

packages/frontend/src/pages/announcements.vue

@@ -5,7 +5,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 
 <template>
 <PageWithHeader v-model:tab="tab" :actions="headerActions" :tabs="headerTabs" :swipable="true">
-	<MkSpacer :contentMax="800">
+	<div class="_spacer" style="--MI_SPACER-w: 800px;">
 		<div class="_gaps">
 			<MkInfo v-if="$i && $i.hasUnreadAnnouncement && tab === 'current'" warn>{{ i18n.ts.youHaveUnreadAnnouncements }}</MkInfo>
 			<MkPagination ref="paginationEl" :key="tab" v-slot="{items}" :pagination="tab === 'current' ? paginationCurrent : paginationPast" class="_gaps">
@@ -39,7 +39,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 				</section>
 			</MkPagination>
 		</div>
-	</MkSpacer>
+	</div>
 </PageWithHeader>
 </template>