RVRNEXT-34 remove placeholders, use labels instead

public/static/js/communities/community_members.js

@@ -1,7 +1,6 @@
 (function () {
     const element = document.getElementById('newMember').elements['user_id'];
     const select = new TomSelect(element, {
-        placeholder: 'User',
         valueField: 'value',
         labelField: 'label',
         searchField: 'label',