Fix error when attempting to delete posts that triggered a notification request (#29666)

db/migrate/20240320163441_change_notification_request_last_status_id_nullable.rb

@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+class ChangeNotificationRequestLastStatusIdNullable < ActiveRecord::Migration[7.1]
+  def change
+    change_column_null :notification_requests, :last_status_id, true
+  end
+end