Replace ripsecrets with gitleaks

What does this merge request do and why?

We've just replaced ripsecrets with gitleaks in gitlab!104303 (merged). This MR does the same for GDK packages.

For context, here's the previous GDK MR !2804 (merged)

And a discussion about switching: gitlab!103705 (comment 1172878236)

Impacted categories

The following categories relate to this merge request:

• gdk-reliability - e.g. When a GDK action fails to complete.
• gdk-usability - e.g. Improvements or suggestions around how the GDK functions.
• gdk-performance - e.g. When a GDK action is slow or times out.

Merge request checklist

• This change is backward compatible. If not, please include steps to communicate to our users.
• Tests added for new functionality. If not, please raise an issue to follow-up.
• Documentation added/updated, if needed.
• gdk doctor test added, if needed.
• Add the ~highlight label if this MR should be included in the CHANGELOG.md.