Fix focused background color of notifications of direct toots (#6021)

app/javascript/styles/mastodon/components.scss

@@ -705,6 +705,10 @@
 
     .status.status-direct {
       background: lighten($ui-base-color, 12%);
+
+      &.muted {
+        background: transparent;
+      }
     }
 
     .detailed-status,