TEAM #1177- Add script to cleanup task definitions in GHA workflow

[coreycarvalho]

Description

This PR introduces a GHA workflow that deregisters all api and celery task definitions except the most recent 10 (for each family). The workflow runs on a cron, every Sunday at 00:00 UTC. There is also a workflow dispatch option that contains a dry run for testing purposes.

issue TEAM 1177

How Has This Been Tested?

As of right now, only dry run has been tested. I am going to test this now without dry run, and I am expecting it to fail on API limits being hit in AWS. Failed workflows on API limits are acceptable for now while we churn through the thousands of task definitions we have to deregister.

Once we churn through those, running this weekly should not trigger API limits.

Dry run: https://github.com/department-of-veterans-affairs/notification-api/actions/runs/12505543172/job/34889065650#step:4:130

Current workflow run deleting task definitions: https://github.com/department-of-veterans-affairs/notification-api/actions/runs/12505695741

Checklist

• I have assigned myself to this PR
• PR has an appropriate title: #9999 - What the thing does
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• I have added tests that prove my fix is effective or that my feature works. Testing guidelines
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• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules
• The ticket was moved into the DEV test column when I began testing this change

[coreycarvalho]

Latest commit adds both jitter and exponential backoff so that we don't hit rate limits in AWS.