Trigger worker on push when the linked PEP project config changes

What does this MR do and why?

Trigger worker on push when the linked PEP project config changes.

This change allows us to update pipeline execution policy metadata when a policy CI configuration changes to know which scanners are enforced by a pipeline execution policy.

References

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• Depends on Analyze pipeline execution policy configs for e... (!178187 - merged).

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How to set up and validate locally

1. Enable feature flag pipeline_execution_policy_analyze_configs
2. Create a project SPP
3. In the project, create policy-ci.yml:

   include:
     - template: Jobs/Dependency-Scanning.gitlab-ci.yml
   
   policy-test-job:
     stage: test
     script:
       - echo 'Policy test job 1'

4. Create another project
5. In this project, go to Secure -> Policies and link the project SPP from step 2. as a policy project
6. Create a new pipeline execution policy:

   pipeline_execution_policy:
     - name: Enforced scans
       description: ''
       enabled: true
       pipeline_config_strategy: inject_ci
       content:
         include:
           - project: <path-to-spp-project>
             file: policy-ci.yml

7. Save the policy
8. Verify using rails console that the metadata has been updated with enforced_scans: ['dependency_scanning']:

   Security::Policy.last.metadata

9. Update the policy-ci.yml directly in the repository, changing the included scanner templates
10. Verify that the metadata in the policy has been updated

Related to #498624 (closed)