change colors for christmas theme

src/client/styles/scss/theme/christmas.scss

@@ -170,6 +170,12 @@ html[dark] {
     }
   }
 
+  .admin-bot-card {
+    .fa.fa-external-link {
+      background-color: transparent !important;
+    }
+  }
+
   .grw-navbar {
     background-image: url('/images/themes/christmas/christmas-navbar.jpg');
   }