This MR replaces generic checkbox

This MR replaces generic checkbox with GitLab UI styled checkbox

Changelog: changed
MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/84863
EE: true

app/views/admin/application_settings/_account_and_limit.html.haml

-= form_for @application_setting, url: general_admin_application_settings_path(anchor: 'js-account-settings'), html: { class: 'fieldset-form', id: 'account-settings' } do |f|
+= gitlab_ui_form_for @application_setting, url: general_admin_application_settings_path(anchor: 'js-account-settings'), html: { class: 'fieldset-form', id: 'account-settings' } do |f|
   = form_errors(@application_setting)
 
   %fieldset

ee/app/views/admin/application_settings/_availability_on_namespace_setting.html.haml

@@ -4,9 +4,6 @@
 
 .form-group
   = form.label :check_namespace_plan, _('Check feature availability on namespace plan'), class: 'label-bold'
-  .form-check
-    = form.check_box :check_namespace_plan, class: 'form-check-input'
-    = form.label :check_namespace_plan, class: 'form-check-label' do
-      = _("Allow use of licensed EE features")
-      .help-block
-        = _("Licensed Enterprise Edition features can be used if the project namespace's plan includes the feature, or if the project is public.")
+  = form.gitlab_ui_checkbox_component :check_namespace_plan,
+    _("Allow use of licensed EE features"),
+    help_text: _("Licensed Enterprise Edition features can be used if the project namespace's plan includes the feature, or if the project is public.")