Default `vue_sidebar_labels` feature flag to true

Default to true so that the issue and MR sidebar labels
widget uses Vue instead of Haml by default

app/controllers/projects/issues_controller.rb

@@ -44,7 +44,7 @@ class Projects::IssuesController < Projects::ApplicationController
     push_frontend_feature_flag(:vue_issuable_sidebar, project.group)
     push_frontend_feature_flag(:tribute_autocomplete, @project)
     push_frontend_feature_flag(:vue_issuables_list, project)
-    push_frontend_feature_flag(:vue_sidebar_labels, @project)
+    push_frontend_feature_flag(:vue_sidebar_labels, @project, default_enabled: true)
   end
 
   before_action only: :show do

app/views/shared/issuable/_sidebar.html.haml

@@ -103,7 +103,7 @@
                     .js-due-date-calendar
 
 
-      - if Feature.enabled?(:vue_sidebar_labels, @project)
+      - if Feature.enabled?(:vue_sidebar_labels, @project, default_enabled: true)
         .js-sidebar-labels{ data: { allow_label_create: issuable_sidebar.dig(:current_user, :can_admin_label).to_s,
           allow_scoped_labels: issuable_sidebar[:scoped_labels_available].to_s,
           can_edit: can_edit_issuable.to_s,

changelogs/unreleased/216881-remove-vue_sidebar_labels-feature-flag.yml

+---
+title: Update issue and MR sidebar labels to use Vue instead of Haml
+merge_request: 44942
+author:
+type: changed

config/feature_flags/development/vue_sidebar_labels.yml

 ---
 name: vue_sidebar_labels
 introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/41561
-rollout_issue_url:
+rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/263440
 group: group::project management
 type: development
-default_enabled: false
+default_enabled: true