Merge branch 'issue_486521-delete_not_used_ch_tables' into 'master'

Remove unused ClickHouse table ci_failed_pipelines_counts_by_namespace

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/182019



Merged-by: Max Woolf <mwoolf@gitlab.com>
Approved-by: Max Woolf <mwoolf@gitlab.com>
Co-authored-by: Felipe Artur <felipefac@gmail.com>