FEATURE: admin can disable flags (#27171)

UI for admins to disable system flags.

app/serializers/post_action_type_serializer.rb

@@ -1,7 +1,16 @@
 # frozen_string_literal: true
 
 class PostActionTypeSerializer < ApplicationSerializer
-  attributes(:id, :name_key, :name, :description, :short_description, :is_flag, :is_custom_flag)
+  attributes(
+    :id,
+    :name_key,
+    :name,
+    :description,
+    :short_description,
+    :is_flag,
+    :is_custom_flag,
+    :enabled,
+  )
 
   include ConfigurableUrls
 
@@ -29,6 +38,10 @@ class PostActionTypeSerializer < ApplicationSerializer
     PostActionType.types[object.id].to_s
   end
 
+  def enabled
+    !!PostActionType.enabled_flag_types[object.id]
+  end
+
   protected
 
   def i18n(field, default: nil, vars: nil)

app/serializers/toggle_flag.rb

@@ -0,0 +1,40 @@
+# frozen_string_literal: true
+
+class ToggleFlag
+  include Service::Base
+
+  contract
+  model :flag
+  policy :invalid_access
+
+  transaction do
+    step :toggle
+    step :log
+  end
+
+  class Contract
+    attribute :flag_id, :integer
+    validates :flag_id, presence: true
+  end
+
+  private
+
+  def fetch_flag(flag_id:)
+    Flag.find(flag_id)
+  end
+
+  def invalid_access(guardian:)
+    guardian.can_toggle_flag?
+  end
+
+  def toggle(flag:)
+    flag.update!(enabled: !flag.enabled)
+  end
+
+  def log(guardian:, flag:)
+    StaffActionLogger.new(guardian.user).log_custom(
+      "toggle_flag",
+      { flag: flag.name, enabled: flag.enabled },
+    )
+  end
+end