Fix styling issue with groups dropdown in IE 10

Fix an issue where the group details container
could horizontally overflow the dropdown menu.

In IE 10 the text did not automatically wrap.

Add flex-shrink so that it will
collapse if necessary.

Card 87

h/static/styles/app.scss

@@ -128,6 +128,7 @@ $group-list-width: 270px;
 
   .group-details {
     margin-right: 20px;
+    flex-shrink: 1;
   }
 
   .share-link-container {