Refactor Indexer index to use react-window

(cherry picked from commit d022679b7dcbce3cec98e6a1fd0879e3c0d92523)

frontend/src/Utilities/Array/getIndexOfFirstCharacter.js

@@ -1,7 +1,5 @@
-import _ from 'lodash';
-
 export default function getIndexOfFirstCharacter(items, character) {
-  return _.findIndex(items, (item) => {
+  return items.findIndex((item) => {
     const firstCharacter = item.sortTitle.charAt(0);
 
     if (character === '#') {