Slow `/api/:version/internal/allowed` endpoint on www-gitlab-com

Details

Originally raised by @stanhu at #220771 (comment 359865749).

The overall durations, however, are still a bit slow (https://log.gprd.gitlab.net/goto/69168bd97565c959f8727a93e738bf9a) at 8 seconds:

gitaly_duration_s and cpu_s look fine. queue_duration_s is concerning (https://log.gprd.gitlab.net/goto/4008dec752ceaa4f0d1da1f70ce812cc):

However, though it looks like the bulk of the time may be rendering view_duration_s (https://log.gprd.gitlab.net/goto/b94c0d3b02e4acb70d0ef775f5a4d3ee):