CI: Use gcr mirror for DinD (17.8 Backport)

What does this MR do and why?

Backport !8257 (merged) to 17-8 stable to avoid hitting DockerHub limits when patch release are about to release.

https://gitlab.com/gitlab-org/distribution/team-tasks/-/issues/1720

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 original MR has been deployed to GitLab.com (not applicable for documentation or spec changes).
• This MR has a severity label assigned (if applicable).

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).