Draft: Handle pipeline execution policy job names

What does this MR do and why?

This change adds suffix for pipeline execution policy jobs to make them distinguishable for the users in the UI.

The suffix is based on the policy index, so all jobs belonging to the same policy will have the same suffix.

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Screenshots or screen recordings

Jobs belonging to the same policy have the same suffix. If the job declares needs, the links between jobs are preserved.

Pipeline execution with jobs that declare needs:

CleanShot_2024-04-24_at_14.50.33

How to set up and validate locally

1. In rails console enable the feature flag

   Feature.enable(:pipeline_execution_policy_type)

2. Create a group
3. Inside the group, create a project SPP group
4. In the project, create a file .gitlab/security-policies/policy.yml with the following content:

   ---
   pipeline_execution_policy:
     - name: Group policy
       description: ''
       enabled: true
       pipeline_config_strategy: inject_ci
       content:
         build job:
           stage: build
           script:
             - sleep 5 && echo "Group building..."
         group build job:
           needs:
             - "build job"
           script:
             - echo "Group policy job"
         group test job:
           script:
             - echo "Hello World from the group policy"

5. Go back to the group and open Secure -> Policies. Click "Edit policy project" and select SPP group.
6. In the group, create a new project SPP project.
7. In the project, create a file .gitlab/security-policies/policy.yml with the following content:

   ---
   pipeline_execution_policy:
     - name: Project policy
       description: ''
       enabled: true
       pipeline_config_strategy: inject_ci
       content:
         build job:
           stage: build
           script:
             - sleep 3 && echo "Policy building..."
         slow project policy build job:
           stage: build
           script:
             - sleep 15 && echo "Slow build completed."
        policy test job with needs:
           stage: test
           needs:
             - "build job"
           script:
             - echo "Project policy job started after build job"
         policy test job:
           stage: test
           script:
             - echo "Policy testing..."

8. Create another project in the group: Test
9. In the project Test, go to Secure -> Policies, edit the policy project and select SPP project
10. In the project Test, create .gitlab-ci.yml:

    build job:
      stage: build
      script:
        - echo "Compiling the code..."
        - echo "Compile complete."
    
    project test job:
      stage: test
      script:
        - echo "Running unit tests... This will take about 60 seconds."
        - echo "Code coverage is 90%"
    
    deploy job:
      stage: deploy
      environment: production
      script:
        - echo "Deploying application..."
        - echo "Application successfully deployed."

11. Go to Pipelines and run pipeline
12. Verify that jobs from both policies are injected into the pipeline
13. Verify that jobs contain suffixes based on the policies they belong to
14. Verify that job dependencies are preserved

Related to #455314 (closed)