ci: Update workflows based on results of last release.

[tippmar-nr]

• Updates deploy_agent.yml to fix an error in the conditional for running the APM update. Also adjusts some of the dependencies for release notes and post-deploy actions.
• Updates `post_deploy.yml' to introduce a 2-minute delay before validating apt and yum, when the workflow is invoked by an external call. This is to give those repos time to refresh their indexes prior to attempting the validation step.
• Fixes a minor typo in publish_release_notes.yml