Added frontend tracking to epic tree

ee/app/assets/javascripts/related_items_tree/constants.js

@@ -58,3 +58,5 @@ export const issueHealthStatusCSSMapping = {
   onTrack: 'status-on-track',
   needsAttention: 'status-needs-attention',
 };
+
+export const trackingNewIssue = 'g_product_planning_epic_new_issue_added_from_epic';

ee/app/assets/javascripts/related_items_tree/store/actions.js

@@ -12,7 +12,7 @@ import {
   relatedIssuesRemoveErrorMap,
 } from '~/related_issues/constants';
 
-import { ChildType, ChildState, idProp, relativePositions } from '../constants';
+import { ChildType, ChildState, idProp, relativePositions, trackingNewIssue } from '../constants';
 
 import epicChildReorder from '../queries/epicChildReorder.mutation.graphql';
 import { processQueryResponse, formatChildItem, gqClient } from '../utils/epic_utils';
@@ -568,6 +568,7 @@ export const createNewIssue = ({ state, dispatch }, { issuesEndpoint, title }) =
   return axios
     .post(issuesEndpoint, { epic_id: epicId, title })
     .then(({ data }) => {
+      Api.trackRedisHllUserEvent(trackingNewIssue);
       dispatch('receiveCreateIssueSuccess', data);
       dispatch('fetchItems', {
         parentItem,