Merge commit 'be991f1d18006a4820c1e9ca6625bf2bd2bfedac' into glitch-soc/merge-upstream

Conflicts:
- `app/models/form/admin_settings.rb`:
  Upstream added the notion of overriden settings, while we had extra code for
  pseudo-settings (only used to combine flavour and skin in a single select
  field).
  Ported upstream changes.
- `config/i18n-tasks.yml`:
  Upstream added `simple_form.overridden` to `ignore_unused`,
  we had `simple_form.glitch_only`.
  Added `simple_form.glitch_only` as well.

app/services/concerns/payloadable.rb

@@ -1,6 +1,8 @@
 # frozen_string_literal: true
 
 module Payloadable
+  include AuthorizedFetchHelper
+
   # @param [ActiveModelSerializers::Model] record
   # @param [ActiveModelSerializers::Serializer] serializer
   # @param [Hash] options
@@ -23,6 +25,6 @@ module Payloadable
   end
 
   def signing_enabled?
-    ENV['AUTHORIZED_FETCH'] != 'true' && !Rails.configuration.x.limited_federation_mode
+    !authorized_fetch_mode?
   end
 end