Add ransackable attributes for Spree::PaymentMethod search in admin

Enhanced the search capabilities in the admin panel by updating
the `allowed_ransackable_attributes` of the `Spree::PaymentMethod` 
model.

This update specifically adds the `name` and `description` fields to the
list of attributes that can be searched using Ransack.

core/app/models/spree/payment_method.rb

@@ -42,6 +42,8 @@ class UnsupportedPaymentMethod < StandardError; end
 
     include Spree::Preferences::StaticallyConfigurable
 
+    self.allowed_ransackable_attributes = %w[name description]
+
     # Custom ModelName#human implementation to ensure we don't refer to
     # subclasses as just "PaymentMethod"
     class ModelName < ActiveModel::Name