Simplify show_service_templates_nav_link logic

Responding to maintainer feedback.
Remove service_templates_enabled
help method and move it's logic into
show_service_templates_nav_link method.

app/helpers/services_helper.rb

@@ -173,12 +173,8 @@ module ServicesHelper
     }
   end
 
-  def service_templates_enabled?
-    Feature.disabled?(:disable_service_templates, type: :development, default_enabled: :yaml)
-  end
-
   def show_service_templates_nav_link?
-    service_templates_enabled?
+    Feature.disabled?(:disable_service_templates, type: :development, default_enabled: :yaml)
   end
 end