chore(client): tweak custom emoji size

packages/frontend/src/components/global/MkCustomEmoji.vue

@@ -41,7 +41,7 @@ let errored = $ref(url.value == null);
 
 <style lang="scss" module>
 .root {
-	height: 2.5em;
+	height: 2em;
 	vertical-align: middle;
 	transition: transform 0.2s ease;