Refactor loading of theme Pro Price helper

Prepending module to the Pro Price helper was causing issues in CI only.
We don't actually have to do this as helper modules are all included
into the same context via ActionView::Base.

lib/helper_patches.rb

@@ -1,8 +1,10 @@
 # Load our helpers
 require 'helpers/donation_helper'
+require 'helpers/alaveteli_pro/alternative_price_text_helper'
 
 Rails.configuration.to_prepare do
   ActionView::Base.send(:include, DonationHelper)
+  ActionView::Base.send(:include, AlaveteliPro::AlternativePriceTextHelper)
 
   ApplicationHelper.class_eval do
     def is_contact_page?
@@ -31,30 +33,4 @@ def hidden_by_excel_analyzer?
 
     prepend ExcelAnalyzerDisableContactUs
   end
-
-  AlaveteliPro::PriceHelper.class_eval do
-    module AlternativePriceText
-      def short_alternative_price_text(price)
-        amount = format_currency(
-          price.unit_amount_with_tax, no_cents_if_whole: true
-        )
-
-        if interval(price) == 'day' && interval_count(price) == 1
-          _('or {{amount}} daily', amount: amount)
-        elsif interval(price) == 'week' && interval_count(price) == 1
-          _('or {{amount}} weekly', amount: amount)
-        elsif interval(price) == 'month' && interval_count(price) == 1
-          _('or {{amount}} monthly', amount: amount)
-        elsif interval(price) == 'year' && interval_count(price) == 1
-          _('or {{amount}} annually', amount: amount)
-        else
-          _('or {{amount}} every {{interval}}',
-            amount: amount,
-            interval: pluralize_interval(price))
-        end
-      end
-    end
-
-    prepend AlternativePriceText
-  end
 end

lib/helpers/alaveteli_pro/alternative_price_text_helper.rb

@@ -0,0 +1,21 @@
+module AlaveteliPro::AlternativePriceTextHelper
+  def alternative_price_text(price)
+    amount = format_currency(
+      price.unit_amount_with_tax, no_cents_if_whole: true
+    )
+
+    if interval(price) == 'day' && interval_count(price) == 1
+      _('or {{amount}} daily', amount: amount)
+    elsif interval(price) == 'week' && interval_count(price) == 1
+      _('or {{amount}} weekly', amount: amount)
+    elsif interval(price) == 'month' && interval_count(price) == 1
+      _('or {{amount}} monthly', amount: amount)
+    elsif interval(price) == 'year' && interval_count(price) == 1
+      _('or {{amount}} annually', amount: amount)
+    else
+      _('or {{amount}} every {{interval}}',
+        amount: amount,
+        interval: pluralize_interval(price))
+    end
+  end
+end

lib/views/alaveteli_pro/plans/_pricing_tiers.html.erb

@@ -16,7 +16,7 @@
       </p>
 
       <p class="price-label-option">
-        <%= link_to short_alternative_price_text(@prices[1]), plan_path(@prices[1]) %>
+        <%= link_to alternative_price_text(@prices[1]), plan_path(@prices[1]) %>
       </p>
     </div>