Centers GIFs in media modal (#36806)

app/javascript/styles/mastodon/components.scss

@@ -6196,6 +6196,8 @@ a.status-card {
   inset-inline-start: 0;
   inset-inline-end: 0;
   bottom: 0;
+  align-items: center;
+  justify-content: space-around; // If set to center, the fullscreen image overlay is misaligned.
 
   > div {
     flex-shrink: 0;