rule manager: Moved metric registration to custom registerer which is already available. (#4961)
rule manager: Moved metric registration to custom registerer which is already available. (#4961)

Signed-off-by: Bartek Plotka <40733124e8bedaac646d3fd1c538b5cb2b6856fe@gmail.com>

Gouthamve/prometheus,Gouthamve/prometheus,Gouthamve/prometheus,alileza/prometheus,GoogleCloudPlatform/prometheus,alileza/prometheus,GoogleCloudPlatform/prometheus,keegancsmith/prometheus,prometheus/prometheus,prometheus/prometheus,alileza/prometheus,alileza/prometheus,kangwoo/prometheus,Gouthamve/prometheus,kangwoo/prometheus,prometheus/prometheus,keegancsmith/prometheus,GoogleCloudPlatform/prometheus,alileza/prometheus,keegancsmith/prometheus,GoogleCloudPlatform/prometheus,prometheus/prometheus,keegancsmith/prometheus,prometheus/prometheus,kangwoo/prometheus,GoogleCloudPlatform/prometheus,kangwoo/prometheus,keegancsmith/prometheus