CI/CD Analytics: Usage metrics by tab

Problem to solve

We currently track "Unique visitors to :group/:project/-/pipelines/charts by month". However, that page has 3 different tabs, which can be bookmarked/navigated as if they are separate pages. So the current usage metrics are not granular enough to understand which tabs are most/least popular. We want more granular usage metrics per @ogolowinski.

Proposal

Add 3 new usage metrics, one for each CI/CD Analytics tab. This can be done using a condition on each call to track_redis_hll_event (example). The condition can check for the GET param called chart. Learn more.

• Pipelines (params[:chart].blank? || params[:chart] == 'pipeline')
• Deployment frequency (params[:chart] == 'deployment-frequency')
• Lead time (params[:chart] == 'lead-time')

Also, add frontend tracking on tab clicks.

Note: The existing page-level usage metric called p_analytics_pipelines_monthly is being deprecated and removed under #345074 (closed).