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

packages/frontend/src/components/MkCustomEmojiDetailedDialog.vue

@@ -7,7 +7,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 <MkModalWindow ref="dialogEl" @close="cancel()" @closed="emit('closed')">
 	<template #header>:{{ emoji.name }}:</template>
 	<template #default>
-		<MkSpacer>
+		<div class="_spacer">
 			<div style="display: flex; flex-direction: column; gap: 1em;">
 				<div :class="$style.emojiImgWrapper">
 					<MkCustomEmoji :name="emoji.name" :normal="true" :useOriginalSize="true" style="height: 100%;"></MkCustomEmoji>
@@ -50,7 +50,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 					</template>
 				</MkKeyValue>
 			</div>
-		</MkSpacer>
+		</div>
 	</template>
 </MkModalWindow>
 </template>