Mark SMTP settings as sensitive

This avoids leaking SMTP credentials during `gitlab-ctl reconfigure`.

Relates to https://gitlab.com/gitlab-org/omnibus-gitlab/-/issues/8867

Changelog: fixed

files/gitlab-cookbooks/gitlab/recipes/gitlab-rails.rb

@@ -363,6 +363,7 @@ templatesymlink "Create a smtp_settings.rb and create a symlink to Rails root" d
   dependent_services.each { |svc| notifies :restart, svc }
   action :delete unless node['gitlab']['gitlab_rails']['smtp_enable']
+  sensitive true
 end
 templatesymlink "Create a gitlab.yml and create a symlink to Rails root" do

files/gitlab-cookbooks/monitoring/recipes/alertmanager.rb

@@ -70,6 +70,7 @@ file 'Alertmanager config' do
   owner prometheus_user
   mode '0644'
   notifies :restart, 'runit_service[alertmanager]'
+  sensitive true
 end
 runtime_flags = PrometheusHelper.new(node).kingpin_flags('alertmanager')