Better handle no (valid) plugin selection

Summary: Little ux tweak, there are some rare scenarios where you can end up in an empty plugin screen, made a small message.

Reviewed By: jknoxville

Differential Revision: D22846396

fbshipit-source-id: 0ad19f1c252112d78a5587e6633fee2d9542d5e1

desktop/static/icons.json

@@ -440,5 +440,8 @@
   ],
   "wireless": [
     16
+  ],
+  "cup-outline": [
+    24
   ]
 }