refactor: flow typing (#1012)

* fix: padding

* fix: Minor button alignment issues

* feat: Add icon to invite people button

* WIP

app/scenes/CollectionPermissions/components/UserListItem.js

@@ -8,7 +8,7 @@ import User from 'models/User';
 type Props = {
   user: User,
   showAdd: boolean,
-  onAdd: () => *,
+  onAdd: () => void,
 };
 
 const UserListItem = ({ user, onAdd, showAdd }: Props) => {