Remove replaced Jira metrics

What does this MR do and why?

Related to https://gitlab.com/gitlab-org/gitlab/-/issues/389428

We added replacement metrics in a previous MR and we want to remove the old ones.

Screenshots or screen recordings

Screenshots are required for UI changes, and strongly recommended for all other merge requests.

How to set up and validate locally

To make sure that Service Ping is still generated correctly, enter the rails console and run:

sp = Gitlab::Usage::ServicePingReport.for(output: :all_metrics_values)

To make sure that the metrics are successfully removed from the payload:

[9] pry(main)> sp.dig('counts', 'projects_jira_cloud_active')
=> nil
[10] pry(main)> sp.dig('counts', 'projects_jira_server_active')
=> nil

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.