Syncing security back to canonical after security release

What does this MR do and why?

Syncs the security 16-4-stable-ee branch back into canonical 16-4-stable-ee after the security release. The automatic syncing failed.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• [-] This MR is backporting a bug fix, documentation update, or spec fix, previously merged in the default branch.
• [-] The MR that fixed the bug on the default branch has been deployed to GitLab.com (not applicable for documentation or spec changes).
• [-] This MR has a severity label assigned (if applicable).
• This MR has been approved by a maintainer (only one approval is required).
• [-] Ensure the e2e:package-and-test-ee job has either succeeded or been approved by a Software Engineer in Test.

This MR is syncing changes from the security mirror that have already been merged and deployed to Gitlab.com, so we can skip these steps.

Note to the merge request author and maintainer

If you have questions about the patch release process, please:

• Refer to the patch release runbook for engineers and maintainers for guidance.
• Ask questions on the #releases Slack channel (internal only).