This provides two prometheus metrics to monitor the rate limiter:
boundary_controller_api_ratelimiter_quota_storage_capacity:
This is a gague that shows the total number of quotas that can be stored
at a given moment by the rate limiter.
boundary_controller_api_ratelimiter_quota_storage_usage:
This is a gague that shows the number of quotas currently being stored
by the limiter. If this becomes equal to the capacity, requests that
would result in a new quota being created will get limited and receive a
429 status code.