Make sidebar scrollable

Summary: Sidebar is now scrollable, when showing too many plugins.

Reviewed By: jknoxville

Differential Revision: D9179312

fbshipit-source-id: bfcd4655a0fbbe91424b88378db3713e68e2cb7f

src/chrome/MainSidebar.js

@@ -36,6 +36,7 @@ const CustomClickableListItem = ClickableListItem.extends({
   display: 'flex',
   alignItems: 'center',
   marginBottom: 2,
+  flexShrink: 0,
 });
 
 const SidebarHeader = FlexBox.extends({