Update Jira issue entity labels with title

The GraphQL API uses title instead of name, and thus the frontend
components use label.title for the label's content.

Adding a title attribute here, and keep name for backwards
compatibility.

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

@@ -30,6 +30,7 @@ module Integrations
       expose :labels do |jira_issue|
         jira_issue.labels.map do |name|
           {
+            title: name,
             name: name,
             color: '#EBECF0',
             text_color: '#283856'

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

@@ -54,6 +54,7 @@ RSpec.describe Integrations::Jira::IssueDetailEntity do
       state: 'closed',
       labels: [
         {
+          title: 'backend',
           name: 'backend',
           color: '#EBECF0',
           text_color: '#283856'

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

@@ -51,6 +51,7 @@ RSpec.describe Integrations::Jira::IssueEntity do
       status: 'To Do',
       labels: [
         {
+          title: 'backend',
           name: 'backend',
           color: '#EBECF0',
           text_color: '#283856'