text: Title: [Integrations UI] Improve Tests for Agent Enrollment Flyout
  Body: Ref #103554
  
  Some tests for the [Agent Enrollment flyout ](https://github.com/elastic/kibana/blob/master/x-pack/plugins/fleet/public/components/agent_enrollment_flyout/agent_enrollment_flyout.test.tsx)are currently being skipped because the `step` component passed into the flyout are not first-class React components. We should update this implementation and improve the tests to assert that the expected steps appear in the UI as appropriate. This should include test cases for custom "View Data" step content, as well as UI Extensions that entirely replace the final step of the flyout, such as APM's implementation.