Expose ci_job_token_scope_enabled in job API

What does this MR do and why?

GitLab introduced the ability to secure a workflow by limiting the scope of CI_JOB_TOKEN (#328553 (closed)). This MR adds the status of that option to the /job endpoint.

An example of where this would be used is with a custom executor that seeks to enforce specific limitations on the scope of token before a job will be accepted. With this, a CI_JOB_TOKEN can be used to verify the setting has been enabled without the need to establish/share a broadly scoped admin level token.

This modification aims to address #337087 (closed) and only adds the new details to the payload of /jobs when a CI_JOB_TOKEN is being used to retrieve information regarding the job itself. Please note, I'm not completely confident in how I've limited the scope by creating a new JobTokensJob entities. However, it seemed like the best option to limit the scope of modification and avoid causing N+1 issues.

How to set up and validate locally

Note, steps assume that you already have a functional runner registered with your local GDK:

1. Via a project's Settings -> CI/CD -> Token Access enable the Limit CI_JOB_TOKEN access
2. Create a test .gitlab-ci.yml file:

job:
  tags: [local]
  script:
    - |
      curl --header "Authorization: Bearer ${CI_JOB_TOKEN}" "${CI_API_V4_URL}/job" | jq

3. Verify the response:

{
  ...
  "project": {
     "ci_job_token_scope_enabled": true
  }
}

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 #337087 (closed)