Only show new dashboard if we have Elasticsearch ability

Summary

The new dashboard uses Elasticsearch for querying charts. This means, the page is not functional when Elasticsearch is not available. This is different compared to Security Insights Vulnerability Report and Depdendencies page: only some filters are gradually being introduced that use Elasticsearch, so the basic page still works without.

If the instance does not Elasticsearch support, supply the old dashboard.

Implementation details

Guard new project- and group-level dashboard not only behind the feature flags, but also behind the accessAdvancedVulnerabilityManagement ability. Check vulnerability_report.vue#L234 for inspiration.