Merge branch 'aa-cleanup-boilerplate-comments-in-metrics' into 'master'

Cleanup boilerplate comments in metrics

See merge request gitlab-org/gitlab!56198

config/metrics/counts_28d/20210222041219_i_quickactions_invite_email_single_monthly.yml

 ---
-# See Usage Ping metrics dictionary docs https://docs.gitlab.com/ee/development/usage_ping/metrics_dictionary.html
 key_path: redis_hll_counters.quickactions.i_quickactions_invite_email_single_monthly
 description:
 product_section: dev

config/metrics/counts_28d/20210222041235_i_quickactions_invite_email_multiple_monthly.yml

 ---
-# See Usage Ping metrics dictionary docs https://docs.gitlab.com/ee/development/usage_ping/metrics_dictionary.html
 key_path: redis_hll_counters.quickactions.i_quickactions_invite_email_multiple_monthly
 description:
 product_section: dev