Disable stale action's debug mode

[sbarrio]

What does this PR do?

This PR disables the stale action debug-only flag meaning that the action will now modify and close issues when run.

Motivation

After validating that the action properly identifies stale issues we can now allow it to run and modify issues instead of doing dry runs.

Additional Notes

Thanks to @mariedm for the support 🙇

Review checklist (to be filled by reviewers)

• Feature or bugfix MUST have appropriate tests
• Make sure you discussed the feature or bugfix with the maintaining team in an Issue
• Make sure each commit and the PR mention the Issue number (cf the CONTRIBUTING doc)
• If this PR is auto-generated, please make sure also to manually update the code related to the change