DEV: Don't attempt to update log if completion request fails. (#321)

We already log the request failure when we raise the exception.

lib/completions/endpoints/base.rb

@@ -105,16 +105,18 @@ module DiscourseAi
 
               return response_data
             ensure
+              if log
                 log.raw_response_payload = response_raw
                 log.response_tokens = tokenizer.size(response_data)
                 log.save!
 
-              if Rails.env.development? && log
+                if Rails.env.development?
                   puts "#{self.class.name}: request_tokens #{log.request_tokens} response_tokens #{log.response_tokens}"
                 end
               end
             end
           end
+        end
 
         def default_options
           raise NotImplementedError