Migrate the 2 `IncrementResourceUsagePerAction` callers in `Gitlab::ApplicationRateLimiter` to `Labkit::RateLimit`. `IncrementResourceUsagePerAction` uses `INCRBYFLOAT` to track fractional resource usage. Labkit currently only supports integer `INCR` counters. This cohort is blocked until a float-cost counting strategy is implemented upstream in labkit-ruby. Known call sites: `lib/gitlab/resource_usage_limiter.rb` (2 call sites) Overarching issue: https://gitlab.com/gitlab-com/gl-infra/production-engineering/-/work_items/28808 Parent epic: https://gitlab.com/groups/gitlab-com/gl-infra/-/work_items/2021 ## Labkit prerequisite Float-cost counting strategy (INCRBYFLOAT) in labkit-ruby. ## TODO - [ ] Create labkit-ruby issue for float-cost counting strategy - [ ] Follow the shadow validation and enforcement flip process from the overarching issue