Improve security widget report summary message by showing the vulnerability counts

Why are we doing this work

Currently for a MR, after the pipeline for the MR completes, a security report summary is shown on the MR page:

We want to improve the summary message by simplifying the wording and using colors to surface the most important information.

Relevant links

Mocks B1 - B7

• B1. No Vulns
• B2. New Vulns
• B3. Job Error
• B4. Report Error
• B5. Use cases: Non-error states
• B6. Use cases: Error States
• B7. Misconfig error help popover

Non-functional requirements

• Documentation: will need to be updated to cover the new messages that can be displayed

Implementation plan

• frontend update the message to show the total count of vulnerabilities and then the breakdown of counts
  • Related files:
    • ee/app/assets/javascripts/vue_shared/security_reports/grouped_security_reports_app.vue
    • ee/app/assets/javascripts/vue_shared/security_reports/store/getters.js
    • ee/app/assets/javascripts/vue_shared/security_reports/store/utils.js
      • This one has groupedTextBuilder, which creates the text