Migrate expiration policy metrics

What does this MR do and why?

This MR migrate counts.projects_with_expiration_policy_enabled(_with_older_than*) metrics family to instrumentation class.

It resolves part of the metrics included in #339315 (closed)

Screenshots or screen recordings

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How to set up and validate locally

Setup (optional)

::ContainerExpirationPolicy.limit(30).update_all(enabled: true)
(::ContainerExpirationPolicy.older_than_options.keys << nil).each_with_index do |value, idx|
  ::ContainerExpirationPolicy.active.order(:project_id).offset(idx * 5).limit(5).update_all(older_than: value)
end

Verfication

payload = ServicePing::BuildPayload.new.execute
puts "enabled: #{payload["counts"]["projects_with_expiration_policy_enabled"]}"
puts "enabled with older_than_unset: #{payload["counts"]["projects_with_expiration_policy_enabled_with_older_than_unset"]}"
puts "enabled with older_than_set_to_7d: #{payload["counts"]["projects_with_expiration_policy_enabled_with_older_than_set_to_7d"]}"
puts "enabled with older_than_set_to_14d: #{payload["counts"]["projects_with_expiration_policy_enabled_with_older_than_set_to_14d"]}"
puts "enabled with older_than_set_to_30d: #{payload["counts"]["projects_with_expiration_policy_enabled_with_older_than_set_to_30d"]}"
puts "enabled with older_than_set_to_60d: #{payload["counts"]["projects_with_expiration_policy_enabled_with_older_than_set_to_60d"]}"
puts "enabled with older_than_set_to_90d: #{payload["counts"]["projects_with_expiration_policy_enabled_with_older_than_set_to_90d"]}"

MR acceptance checklist

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