docs: Remove the link to the CI/CD Overview page, which is redundant

All the sections inside "Third-Party Integrations" are top-level categories and do not have their own pages, except for CI/CD which has a direct link.

UAC: The sidebar "CI/CD" text opens the sub-items, but does not direct the user to the "CI/CD Overview" page which should not exist (similar to all other categories in the Third-Party Integration secrion