fix up diego spec

Signed-off-by: Momchil Atanasov <m.momchil@gmail.com>
implement purge and reseed functionality for service usage events.

- an admin can curl
  '/v2/service_usage_events/destructively_purge_all_and_reseed_existing_instances' endpoint to do the purge and reset

[#70316500]
permit absence of detected_start_command

Signed-off-by: Momchil Atanasov <m.momchil@gmail.com>