Remove annoying Notification#cache_ids scope warning (#8333)

app/models/notification.rb

@@ -39,8 +39,6 @@ class Notification < ApplicationRecord
   validates :account_id, uniqueness: { scope: [:activity_type, :activity_id] }
   validates :activity_type, inclusion: { in: TYPE_CLASS_MAP.values }
 
-  scope :cache_ids, -> { select(:id, :updated_at, :activity_type, :activity_id) }
-
   scope :browserable, ->(exclude_types = []) {
     types = TYPE_CLASS_MAP.values - activity_types_from_types(exclude_types + [:follow_request])
     where(activity_type: types)
@@ -68,6 +66,10 @@ class Notification < ApplicationRecord
   end
 
   class << self
+    def cache_ids
+      select(:id, :updated_at, :activity_type, :activity_id)
+    end
+
     def reload_stale_associations!(cached_items)
       account_ids = (cached_items.map(&:from_account_id) + cached_items.map { |item| item.target_status&.account_id }.compact).uniq