Simplify calls to content_block helper

All calls were using `I18n.locale` as the second parameter, so we might
as well make it optional.

app/components/layout/social_component.rb

@@ -26,6 +26,6 @@ class Layout::SocialComponent < ApplicationComponent
     end
 
     def footer_content_block
-      content_block("footer", I18n.locale)
+      content_block("footer")
     end
 end

app/components/layout/top_links_component.rb

@@ -8,6 +8,6 @@ class Layout::TopLinksComponent < ApplicationComponent
   private
 
     def top_links_content_block
-      content_block("top_links", I18n.locale)
+      content_block("top_links")
     end
 end