Address backend reviewer feedback

Memoize issue_json method

app/helpers/services_helper.rb

@@ -128,10 +128,10 @@ module ServicesHelper
     !Gitlab.com?
   end
 
-  def jira_issue_breadcrumb_link(issue_json)
+  def jira_issue_breadcrumb_link(issue_reference)
     link_to '', { class: 'gl-display-flex gl-align-items-center gl-white-space-nowrap' } do
       icon = image_tag image_path('illustrations/logos/jira.svg'), width: 15, height: 15, class: 'gl-mr-2'
-      [icon, issue_json[:references][:relative]].join.html_safe
+      [icon, issue_reference].join.html_safe
     end
   end
 

ee/app/controllers/projects/integrations/jira/issues_controller.rb

@@ -14,6 +14,7 @@ module Projects
 
         before_action :check_feature_enabled!
         before_action :check_issues_show_enabled!, only: :show
+        before_action :issue_json, only: :show
 
         before_action do
           push_frontend_feature_flag(:jira_issues_integration, project, type: :licensed, default_enabled: true)
@@ -37,8 +38,6 @@ module Projects
         end
 
         def show
-          @issue = issue_json
-
           respond_to do |format|
             format.html
             format.json do
@@ -66,8 +65,8 @@ module Projects
         end
 
         def issue_json
-          ::Integrations::Jira::IssueDetailSerializer.new
-            .represent(project.jira_service.find_issue(params[:id], rendered_fields: true), project: project)
+          @issue_json ||= ::Integrations::Jira::IssueDetailSerializer.new
+              .represent(project.jira_service.find_issue(params[:id], rendered_fields: true), project: project)
         end
 
         def finder

ee/app/views/projects/integrations/jira/issues/show.html.haml

 - add_to_breadcrumbs _('Jira Issues'), project_integrations_jira_issues_path(@project)
-- breadcrumb_title jira_issue_breadcrumb_link(@issue)
-- page_title @issue[:title]
+- breadcrumb_title jira_issue_breadcrumb_link(@issue_json[:references][:relative])
+- page_title @issue_json[:title]
 
 .js-jira-issues-show-app{ data: jira_issues_show_data }