Replace underscore with lodash in notes

app/assets/javascripts/notes/components/comment_form.vue

 <script>
 import $ from 'jquery';
 import { mapActions, mapGetters, mapState } from 'vuex';
-import _ from 'underscore';
+import { isEmpty } from 'lodash';
 import Autosize from 'autosize';
 import { __, sprintf } from '~/locale';
 import TimelineEntryItem from '~/vue_shared/components/notes/timeline_entry_item.vue';
@@ -161,7 +161,7 @@ export default {
       'toggleStateButtonLoading',
     ]),
     setIsSubmitButtonDisabled(note, isSubmitting) {
-      if (!_.isEmpty(note) && !isSubmitting) {
+      if (!isEmpty(note) && !isSubmitting) {
         this.isSubmitButtonDisabled = false;
       } else {
         this.isSubmitButtonDisabled = true;

app/assets/javascripts/notes/components/diff_discussion_header.vue

 <script>
 import { mapActions } from 'vuex';
-import _ from 'underscore';
+import { escape } from 'lodash';
 
 import { s__, __, sprintf } from '~/locale';
 import { truncateSha } from '~/lib/utils/text_utility';
@@ -45,7 +45,7 @@ export default {
       return this.notes.length > 1 ? this.lastNote.created_at : null;
     },
     headerText() {
-      const linkStart = `<a href="${_.escape(this.discussion.discussion_path)}">`;
+      const linkStart = `<a href="${escape(this.discussion.discussion_path)}">`;
       const linkEnd = '</a>';
 
       const { commit_id: commitId } = this.discussion;

app/assets/javascripts/notes/components/noteable_note.vue

 <script>
 import $ from 'jquery';
 import { mapGetters, mapActions } from 'vuex';
-import { escape } from 'underscore';
+import { escape } from 'lodash';
 import draftMixin from 'ee_else_ce/notes/mixins/draft';
 import { truncateSha } from '~/lib/utils/text_utility';
 import TimelineEntryItem from '~/vue_shared/components/notes/timeline_entry_item.vue';

app/assets/javascripts/notes/components/toggle_replies_widget.vue

 <script>
-import _ from 'underscore';
+import { uniqBy } from 'lodash';
 import Icon from '~/vue_shared/components/icon.vue';
 import UserAvatarLink from '~/vue_shared/components/user_avatar/user_avatar_link.vue';
 import TimeAgoTooltip from '~/vue_shared/components/time_ago_tooltip.vue';
@@ -27,7 +27,7 @@ export default {
     uniqueAuthors() {
       const authors = this.replies.map(reply => reply.author || {});
 
-      return _.uniq(authors, author => author.username);
+      return uniqBy(authors, author => author.username);
     },
     className() {
       return this.collapsed ? 'collapsed' : 'expanded';

app/assets/javascripts/notes/stores/getters.js

-import _ from 'underscore';
+import { flattenDeep } from 'lodash';
 import * as constants from '../constants';
 import { collapseSystemNotes } from './collapse_utils';
 
@@ -50,7 +50,7 @@ const isLastNote = (note, state) =>
   !note.system && state.userData && note.author && note.author.id === state.userData.id;
 
 export const getCurrentUserLastNote = state =>
-  _.flatten(reverseNotes(state.discussions).map(note => reverseNotes(note.notes))).find(el =>
+  flattenDeep(reverseNotes(state.discussions).map(note => reverseNotes(note.notes))).find(el =>
     isLastNote(el, state),
   );