Modify archive rate limit to throttle by user

In the previous implementation, an unauthenticated user attempting to
download the archive repeatedly would interfere with authenticated
users. To avoid that, we increase the scope of the limiter to include
the user.

lib/gitlab/rate_limit_helpers.rb

@@ -11,7 +11,7 @@ module Gitlab
 
       key = ARCHIVE_RATE_THROTTLE_KEY
 
-      if rate_limiter.throttled?(key, scope: [project], threshold: archive_rate_threshold_by_user(user))
+      if rate_limiter.throttled?(key, scope: [project, user], threshold: archive_rate_threshold_by_user(user))
         rate_limiter.log_request(request, "#{key}_request_limit".to_sym, user)
 
         return true

spec/lib/gitlab/rate_limit_helpers_spec.rb

@@ -43,6 +43,7 @@ describe Gitlab::RateLimitHelpers, :clean_gitlab_redis_shared_state do
         end
 
         expect(class_instance.archive_rate_limit_reached?(nil, project)).to be_truthy
+        expect(class_instance.archive_rate_limit_reached?(user, project)).to be_falsey
       end
     end
   end