Add lazy load to emoji-mart (#16907)

* perf: lazyload emoji-mart!

* Bump lazyload

app/javascript/styles/mastodon/emoji_picker.scss

@@ -169,14 +169,15 @@
   }
 
   &:hover::before {
-    z-index: 0;
+    z-index: -1;
     content: "";
     position: absolute;
     top: 0;
     left: 0;
     width: 100%;
     height: 100%;
-    background-color: rgba($ui-secondary-color, 0.7);
+    // background-color: rgba($ui-secondary-color, 0.7);
+    background-color: #f4f4f4;
     border-radius: 100%;
   }
 }