Add comparison pipelines into policy bot comment

What does this MR do and why?

This MR adds a list of pipelines used for evaluation of scan_finding policies into the policy bot comment.

Depends on !147830 (merged).

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

With multiple report_types:

How to set up and validate locally

1. Create a project
2. Enable feature flag in rails console:

   Feature.enable(:save_policy_violation_data, Project.last)

3. Create .gitlab-ci.yml:

   build-job:
     script:
       - echo "Compiling the code..."
       - echo "Compile complete."

4. Go to Secure -> Policies and create a new Merge request approval policy with the following YAML:

   type: approval_policy
   name: New scans
   description: ''
   enabled: true
   rules:
     - type: scan_finding
       scanners: []
       vulnerabilities_allowed: 0
       severity_levels: []
       vulnerability_states: []
       branch_type: protected
   actions:
     - type: require_approval
       approvals_required: 1
       role_approvers:
         - developer

5. Configure with merge request & merge
6. Go back to the project and update .gitlab-ci.yml in a new MR, adding a container scanning template and a vulnerable image:

   include:
     - template: Jobs/Container-Scanning.gitlab-ci.yml
   
   container_scanning:
     variables:
       CS_IMAGE: 'citizenstig/dvwa:latest'
   
   build-job:
     script:
       - echo "Compiling the code..."
       - echo "Compile complete."

7. Verify that bot comment is created and includes the comparison pipelines section

Related to #433403 (closed)