Simplify adding a type-component for generic vulnerability reports

What does this MR do?

This is a minor refactor that will make it simpler to add a new component for rendering a generic vulnerability report type going forward.

It also adds an afterEach cleanup to existing specs.

Screenshots

no visible changes - should stay the same

How to test this?

1. Create a new project, give it a gitlab-ci.yml file with the following contents:

stages:
    - dast

dast:
  stage: dast 
  image: alpine:3.10.2
  script:
    - pwd
  artifacts:
    reports:
      dast: dast.json

1. Download https://gitlab.com/-/snippets/2108509 and add it to the project file dast.json
2. Run a pipeline, view vulnerabilities

Does this MR meet the acceptance criteria?

Conformity

• 📋 Does this MR need a changelog?
  • I have included a changelog entry.
  • I have not included a changelog entry because there are no user-facing changes.
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team