Set low priority for scheduled runs

[castrodd]

This PR sets the Priority for scheduled pipeline runs to be low. This is part of an effort to reduce the daily deadlock that we are facing with our various pipelines.

It also reschedules these pipeline runs to 2am UTC.

Pull request checklist

• My changes do not require documentation changes
  • Otherwise: Documentation issue linked to PR
• My changes should not be added to the release notes for the next release
  • Otherwise: I've added my notes to release_notes.md
• My changes do not need to be backported to a previous version
  • Otherwise: Backport tracked by issue/PR #issue_or_pr
• I have added all required tests (Unit tests, E2E tests)

Additional information

Additional PR information