chore(ci): add cleanup script on CI for atlas envs

[kmruiz]

Proposed changes

Runs a nightly script that cleans up stale test environments. This is necessary because in cloud-env there might be hiccups and tell a cluster was going to be deleted but then it's not.

Checklist

• I have signed the MongoDB CLA

[Copilot]

Pull Request Overview

This PR adds automated cleanup functionality for stale Atlas test environments by introducing a nightly CI job that removes old test projects and their associated clusters.

• Implements a cleanup script that identifies and removes test projects older than 24 hours
• Adds a GitHub Actions workflow that runs the cleanup script nightly via cron schedule
• Provides manual trigger capability through workflow_dispatch for on-demand cleanup

Reviewed Changes

Copilot reviewed 2 out of 8 changed files in this pull request and generated 3 comments.

File	Description
scripts/cleanupAtlasTestLeftovers.test.ts	Implements the cleanup logic to find and delete stale Atlas test projects and clusters
.github/workflows/cleanup-atlas-env.yml	Defines the CI workflow that runs the cleanup script on a nightly schedule

[coveralls]

Pull Request Test Coverage Report for Build 18194665523

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
• To avoid this issue with future PRs, see these Recommended CI Configurations.
• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.009%) to 82.501%

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Totals
Change from base Build 18192383441:	-0.009%
Covered Lines:	5296
Relevant Lines:	6308

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💛 - Coveralls