Extract payment method logic from OrderPaymentFinder into the orders helper

app/helpers/admin/orders_helper.rb

@@ -9,5 +9,9 @@ module Admin
         adjustment.originator_type == "Spree::ShippingMethod"
       end
     end
+
+    def last_payment_method(order)
+      OrderPaymentFinder.new(order).last_payment&.payment_method
+    end
   end
 end

app/services/order_payment_finder.rb

@@ -1,7 +1,11 @@
 # frozen_string_literal: true
 
-module OrderPaymentFinder
-  def self.last_payment_method(order)
+class OrderPaymentFinder
+  def initialize(order)
+    @order = order
+  end
+
+  def last_payment
     # `max_by` avoids additional database queries when payments are loaded
     # already. There is usually only one payment and this shouldn't cause
     # any overhead compared to `order(:created_at).last`. Using `last`
@@ -9,6 +13,6 @@ module OrderPaymentFinder
     #
     # We are not using `updated_at` because all payments are touched when the
     # order is updated and then all payments have the same `updated_at` value.
-    order.payments.max_by(&:created_at)&.payment_method
+    @order.payments.max_by(&:created_at)
   end
 end

app/views/spree/order_mailer/_payment.html.haml

@@ -8,7 +8,7 @@
     = t :email_payment_summary
 %h4
   = t :email_payment_method
-  %strong=  OrderPaymentFinder.last_payment_method(@order)&.name
+  %strong=  last_payment_method(@order)&.name
 %p
-  %em= OrderPaymentFinder.last_payment_method(@order)&.description
+  %em= last_payment_method(@order)&.description
 %p  

app/views/spree/shared/_order_details.html.haml

@@ -13,9 +13,9 @@
     .pad
       .text-big
         = t :order_payment
-        %strong=  OrderPaymentFinder.last_payment_method(order)&.name
+        %strong=  last_payment_method(order)&.name
       %p.text-small.text-skinny.pre-line
-        %em= OrderPaymentFinder.last_payment_method(order)&.description
+        %em= last_payment_method(order)&.description
 
     .order-summary.text-small
       %strong