Add License checks to AgentAuthorizationsFinder

What does this MR do and why?

The CI/CD tunnel's ci_user and ci_job impersonation features are EE-only, so these should only be returned when the license is available. We check the license on the CI job's project under the assumption that this project and the agent fall under the same license.

This is not a user facing change, so I have not included a changelog.

Screenshots or screen recordings

KUBECONFIG still gets populated with these changes:

How to set up and validate locally

1. GDK needs a runner attached, and the gitlab-k8s-agent enabled

2. Enable the feature flag group_authorized_agents:

   Feature.enable(:group_authorized_agents)

3. Add an agent with configuration project gitlab-agent-testing/config with the following configuration:

   # config/.gitlab/agents/first/config.yaml
   ci_access:
     projects:
       - id: gitlab-agent-testing/ci-project # <-- We will run CI/CD in here

4. In a separate project, gitlab-agent-testing/ci-project, add the following .gitlab-ci.yml:

   # .gitlab-ci.yml
   test:
     image: registry.gitlab.com/gitlab-org/cluster-integration/helm-install-image/releases/3.6.3-kube-1.17.17-alpine-3.14
     script:
       - kubectl config get-contexts

5. View the job logs for the test job

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.