Remove translateZ(0) on modal overlay (#5478)

app/javascript/styles/mastodon/components.scss

@@ -3067,7 +3067,6 @@ button.icon-button.active i.fa-retweet {
   right: 0;
   bottom: 0;
   background: rgba($base-overlay-background, 0.7);
-  transform: translateZ(0);
 }
 
 .modal-root__container {