Fix for not building sitemap without videos

[murty2]

spree_videos gem is now outdated. I still want to use spree_sitemap without product videos for products

--- spree_defaults.rb.orig      2021-07-26 18:33:27.525570670 -0400
+++ spree_defaults.rb   2021-07-26 18:32:41.590569918 -0400
@@ -34,7 +34,7 @@
   def add_product(product, options = {})
     opts = options.merge(lastmod: product.updated_at) 

-    if gem_available?('spree_videos') && product.videos.present?
+    if gem_available?('spree_videos') && defined? product.videos
       # TODO: add exclusion list configuration option
       # https://sites.google.com/site/webmasterhelpforum/en/faq-video-sitemaps#multiple-pages

If anybody has a better patch, please let me know.