Resolve "Add generic 'metrics' report type to merge requests" frontend

What does this MR do?

Implement the frontend custom metrics on the merge request page.

No Changes

One Change

Two Changes

Overflowing List

Loading List

Error loading list

New and Removed Metrics

• Create ee/app/assets/javascripts/vue_shared/custom_metrics/ folder containing:
  • grouped_custom_metrics_app.vue
  • /store similar to ee/app/assets/javascripts/vue_shared/security_reports/store
• reuse report components from app/assets/javascripts/reports/components
• add grouped_custom_metrics_app component to ee/app/assets/javascripts/vue_merge_request_widget/mr_widget_options.vue
• pass the endpoint to the grouped_custom_metrics_app component
• Create spec for grouped_custom_metrics_app and its store

What are the relevant issue numbers?

#9788 (closed)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated via this MR
• Documentation reviewed by technical writer or follow-up review issue created
• Tests added for this feature/bug
• Tested in all supported browsers
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• Conforms to the database guides
• Link to e2e tests MR added if this MR has Requires e2e tests label. See the Test Planning Process.
• EE specific content should be in the top level /ee folder
• For a paid feature, have we considered GitLab.com plans, how it works for groups, and is there a design for promoting it to users who aren't on the correct plan?
• Security reports checked/validated by reviewer