Use lodash instead of underscore in frequent items

app/assets/javascripts/frequent_items/components/frequent_items_list_item.vue

 <script>
 /* eslint-disable vue/require-default-prop */
-import _ from 'underscore';
+import { isEmpty, isString } from 'lodash';
 import Identicon from '~/vue_shared/components/identicon.vue';
 import highlight from '~/lib/utils/highlight';
 import { truncateNamespace } from '~/lib/utils/text_utility';
@@ -39,7 +39,7 @@ export default {
   },
   computed: {
     hasAvatar() {
-      return _.isString(this.avatarUrl) && !_.isEmpty(this.avatarUrl);
+      return isString(this.avatarUrl) && !isEmpty(this.avatarUrl);
     },
     truncatedNamespace() {
       return truncateNamespace(this.namespace);

app/assets/javascripts/frequent_items/components/frequent_items_search_input.vue

 <script>
-import _ from 'underscore';
+import { debounce } from 'lodash';
 import { mapActions } from 'vuex';
 import Icon from '~/vue_shared/components/icon.vue';
 import eventHub from '../event_hub';
@@ -21,7 +21,7 @@ export default {
     },
   },
   watch: {
-    searchQuery: _.debounce(function debounceSearchQuery() {
+    searchQuery: debounce(function debounceSearchQuery() {
       this.setSearchQuery(this.searchQuery);
     }, 500),
   },

app/assets/javascripts/frequent_items/utils.js

-import _ from 'underscore';
+import { take } from 'lodash';
 import { GlBreakpointInstance as bp } from '@gitlab/ui/dist/utils';
 import sanitize from 'sanitize-html';
 import { FREQUENT_ITEMS, HOUR_IN_MS } from './constants';
@@ -31,7 +31,7 @@ export const getTopFrequentItems = items => {
     return 0;
   });
 
-  return _.first(frequentItems, frequentItemsCount);
+  return take(frequentItems, frequentItemsCount);
 };
 
 export const updateExistingFrequentItem = (frequentItem, item) => {