Remove backend for editing of Jira labels

Feature is will no longer be implemented

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

@@ -15,7 +15,6 @@ module Projects
         before_action :check_feature_enabled!
         before_action only: :show do
           push_frontend_feature_flag(:jira_issue_details_edit_status, project, default_enabled: :yaml)
-          push_frontend_feature_flag(:jira_issue_details_edit_labels, project, default_enabled: :yaml)
         end
 
         rescue_from ::Projects::Integrations::Jira::IssuesFinder::Error, with: :render_error
@@ -44,11 +43,6 @@ module Projects
           end
         end
 
-        def labels
-          # This implementation is just to mock the endpoint, to be implemented https://gitlab.com/gitlab-org/gitlab/-/issues/330778
-          render json: issue_json[:labels]
-        end
-
         private
 
         def visitor_id

ee/app/helpers/ee/integrations_helper.rb

@@ -53,7 +53,6 @@ module EE
 
     def jira_issues_show_data
       {
-        issue_labels_path: labels_project_integrations_jira_issue_path(@project, params[:id]),
         issues_show_path: project_integrations_jira_issue_path(@project, params[:id], format: :json),
         issues_list_path: project_integrations_jira_issues_path(@project)
       }

ee/app/serializers/integrations/jira_serializers/issue_entity.rb

@@ -32,7 +32,6 @@ module Integrations
       expose :labels do |jira_issue|
         jira_issue.labels.map do |name|
           {
-            id: name,
             title: name,
             name: name,
             color: '#0052CC',

ee/config/routes/project.rb

@@ -112,11 +112,7 @@ constraints(::Constraints::ProjectUrlConstrainer.new) do
 
         namespace :integrations do
           namespace :jira do
-            resources :issues, only: [:index, :show] do
-              member do
-                get :labels
-              end
-            end
+            resources :issues, only: [:index, :show]
           end
 
           namespace :zentao do

ee/spec/helpers/ee/integrations_helper_spec.rb

@@ -102,7 +102,6 @@ RSpec.describe EE::IntegrationsHelper do
 
     it 'includes Jira issues show data' do
       is_expected.to include(
-        issue_labels_path: "/#{project.full_path}/-/integrations/jira/issues/FE-1/labels",
         issues_show_path: "/#{project.full_path}/-/integrations/jira/issues/FE-1.json",
         issues_list_path: "/#{project.full_path}/-/integrations/jira/issues"
       )

ee/spec/serializers/integrations/jira_serializers/issue_detail_entity_spec.rb

@@ -86,7 +86,6 @@ RSpec.describe Integrations::JiraSerializers::IssueDetailEntity do
       state: 'closed',
       labels: [
         {
-          id: 'backend',
           title: 'backend',
           name: 'backend',
           color: '#0052CC',

ee/spec/serializers/integrations/jira_serializers/issue_entity_spec.rb

@@ -53,7 +53,6 @@ RSpec.describe Integrations::JiraSerializers::IssueEntity do
       status: 'To Do',
       labels: [
         {
-          id: 'backend',
           title: 'backend',
           name: 'backend',
           color: '#0052CC',