Add support for code to graphql generic security report

What does this MR do and why?

It adds support for rendering the code report type within the GraphQL version of the security pipeline modal.

Screenshots or screen recordings

How to set up and verify

Setup

1. Have the related FF enabled: echo "Feature.enable(:pipeline_security_dashboard_graphql)" | rails c
2. You'll need an EE License
3. You'll need to have runners enabled (See $2408961 for setting up a runner)
4. Import https://gitlab.com/gitlab-examples/security/security-reports
5. Run a pipeline on master

Validation

1. Go to the pipeline's security report tab
2. Click on the finding with the title "X-Frame-Options Header Not Set"
3. Verify that the code type renders as expected

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #386151 (closed)