fix more-options overlay not actually being an overlay :)

res/css/components/poll.less

@@ -110,6 +110,7 @@
         padding: 1rem 0;
         position: absolute;
         bottom: 0; left: 0; right: 0;
+        z-index: 1;
         background: linear-gradient(transparent, #f9f9f9 80%, #f9f9f9);
     }
 }