Try to fix EasySearch syntax.

Thanks to xet7 !

client/components/import/import.js

@@ -311,5 +311,5 @@ BlazeComponent.extendComponent({
 }).register('importMapMembersAddPopup');
 
 Template.importMapMembersAddPopup.helpers({
-  searchIndex: () => Users.search_index,
+  searchIndex: () => UserSearchIndex,
 })

client/components/sidebar/sidebar.js

@@ -1391,7 +1391,7 @@ BlazeComponent.extendComponent({
 }).register('addMemberPopup');
 
 Template.addMemberPopup.helpers({
-  searchIndex: () => Users.search_index,
+  searchIndex: () => UserSearchIndex,
 })
 
 BlazeComponent.extendComponent({

models/users.js

@@ -537,10 +537,9 @@ Users.allow({
 
 // Search a user in the complete server database by its name, username or emails adress. This
 // is used for instance to add a new user to a board.
-const searchInFields = ['username', 'profile.fullname', 'emails.address'];
-Users.search_index = new Index({
+UserSearchIndex = new Index({
   collection: Users,
-  fields: searchInFields,
+  fields: ['username', 'profile.fullname', 'emails.address'],
   engine: new MongoDBEngine(),
 });