Wizard#logo use image_path over image_url.

- `image_path` computes the asset path including configured asset host
  and digest. This fixes an issue where compiled assets and assets
  stored in a CDN where not referenced correctly.

app/models/solidus_paypal_commerce_platform/wizard.rb

@@ -34,7 +34,7 @@ def nonce
     private
 
     def logo
-      ActionController::Base.helpers.image_url(::Spree::Config[:admin_interface_logo])
+      ActionController::Base.helpers.image_path(::Spree::Config[:admin_interface_logo])
     end
   end
 end