AI Policy: Bulk update PR templates across DSACMS repositories with new AI Usage section

## MENTOR
- @natalialuzuriaga, @decause-gov
- Software Engineers, CMS OSPO, DSACMS repository management + outbounding, AI policy
- #dsac-ospo on Slack

## BRIEF DESCRIPTION

The OSPO shipped the new DSACMS AI Policy. In the spirit of transparency and attribution, we made a new addition to our PR templates - an AI usage section.

We would like to update PULL_REQUEST_TEMPLATE.md across all repositories in DSACMS to add this new section using the [addFilesToRepos](https://github.com/DSACMS/repo-scaffolder/blob/main/.github/actions.md#adding-files) workflow in repo-scaffolder

Relevant resources:
- https://dsacms.github.io/ospo-guide/outbound/gen-ai-policy/
- https://github.com/DSACMS/ospo-guide/pull/130

## SCOPING
1-3 days

## SKILLS NEEDED
CI/CD, GitHub Actions, shell scripting

## REQUIRED DELIVERABLES
Make as clear of a step-by-step list as you can

**Verifying that addFilesToRepos workflow works correctly**
We would like to use [addFilesToRepos](https://github.com/DSACMS/repo-scaffolder/blob/main/.github/actions.md#adding-files) to do this work.
1. In a separate GitHub organization, add the workflow and test within the organization to verify functionality. @natalialuzuriaga has her own test organization (https://github.com/natalialuzuriaga-testing-org) she can provide you access where you can set this up and test.
2. If there are any bugs, work with the mentors to fix them. We are also very open to ideas to make the workflow more useful to do this specific rotation as well as other use cases -- please propose them to the mentors!

**Updating PULL_REQUEST_TEMPLATE.md across all repos in DSACMS**
1. Create a PR updating the PULL_REQUEST_TEMPLATE.md in repo-scaffolder. Be sure to tag the mentors of this ticket in the PR review. When this PR is merged, the syncRepoTemplate.yml workflow triggers. This should update and create a PR on the template repositories (e.g. www.github.com/DSACMS/tier2, www.github.com/DSACMS/tier3, www.github.com/DSACMS/tier4) updating them. You can approve and merge this PR.
2. Browse all DSACMS repositories. Identify repositories contain old versions of PULL_REQUEST_TEMPLATE.md l that we need to update. Also identify active Tier 2-4 repositories that do not have a PULL_REQUEST_TEMPLATE.md because we want to add this template to those repositories too!
3. Use the addFilesToRepos workflow to make this update. Be sure to tag the mentors of this ticket in the PR review

## DESIRED DELIVERY WINDOW
- Any

## NOTES/INSPO
Great beginner friendly ticket to learn GitHub Actions, CI/CD, and Devops!

As you are doing this work, you may find that the workflows may have bugs or could be refactored to better automate this task, we are very open to ideas and improvements!

# ACKNOWLEDGEMENTS
- [X] - Yes, I agree to spend file a project proposal ticket
- [X] - Yes, I agree this project falls within a 2 week or less (ideally less) scope of time
- [X] - Yes, I agree to spend an hour per week of office hours and 1x1 mentoring
- [X] - Yes, I agree to spend an hour at the end of the sprint for filling out a Retro Template