Update design of collection accounts editor (#38712)

app/javascript/mastodon/components/empty_state/empty_state.module.scss

@@ -35,3 +35,12 @@
     text-wrap: pretty;
   }
 }
+
+[data-color-scheme='dark'] .defaultImage {
+  --color-skin-1: #3a3a50;
+  --color-skin-2: #67678e;
+  --color-skin-3: #44445f;
+  --color-outline: #21212c;
+  --color-shadow: #181820;
+  --color-highlight: #b2b1c8;
+}