Frontend: Add code acceptance rate to User metrics table

Proposal

The user metrics table is being introduced in Frontend: User metrics table - first iteration (#574420 - closed) • Ezekiel Kigbo • 18.7 with data available at the time of creating this issue.

The table above includes code_suggestion_accepted_in_ide. The Code suggestions shown count per user metrics will be exposed as part of https://gitlab.com/gitlab-org/gitlab/-/issues/570984+s.

Once available, we need to add the code suggestions acceptance rate per user metric to the user metrics table by calculating code_suggestion_accepted_in_ide / code_suggestion_shown_in_ide per user.

Implementation

• Extend data source
• Update table visualization
• Update documentation