fix(sidekiq-alerts): use 1h/5m burn rates instead of 6h/30m

fix(sidekiq-alerts): use 1h/5m burn rates instead of 6h/30m

6h and 30m burn rates are not available in sli_aggregations: recording rules in Mimir.

gitlab-com/gl-infra/scalability#2769 (comment 1876251575)