Fixed direction link for cost-data

Why is this change being made?

https://master-patch-f90a.about.gitlab-review.app/handbook/product/categories/#scalability-group now links to the correct direction page for Infrastructure Cost Data https://master-patch-f90a.about.gitlab-review.app/direction/saas-platforms/cost-data.

Currently, we are seeing a link https://about.gitlab.com/handbook/product/categories/direction/saas_platforms/cost-data/ which is 404 Not found.

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