Move pull-gitleaks workflow into Pull Request Pipeline workflow

[triffer]

Description
In API Gateway we have the workflow pull-gitleaks that runs in scope of pull requests. We already have the workflow Pull Request Pipeline that encapsulates other jobs running in the scope of pull requests. We should move the separate pull-gitleaks workflow into the existing pull request workflow to simplify our workflow configuration.

Motivation

Fulfill AC Reduce job runs count, ensure all jobs have clear responsibility and meaning from our team goal.

ToDo [Developer]

• ...

PRs

AC [PO]

• pull-gitleaks runs as job of Pull Request workflow

Attachments

• Istio pull-gitleaks workflow
• Istio Pull Request Pipeline workflow