Fix GitLab AppSec Inventory link
What does this MR do?
Fixes the link to the GitLab AppSec Inventory on the Application Security page.
The link pointed to an outdated location (/handbook/product/ux/navigation/inventory/), likely broken by page refactors over time. Both references are updated to the correct page:
/handbook/security/product-security/security-platforms-architecture/application-security/inventory/
Changes
- Updated the "GitLab Secure Tools coverage" section link
- Updated the "GitLab Inventory" section link