fix: Resolve "Improve behaviour of Features page sub-links"

Step 1: What is changing in this MR?

• Reverts platform table external links MR
• Removes card animation to prevent content shifting.
• Adds scroll-margin-top property to account for top navigation covering anchored sections.
• Adds feature category description ( content coming from content/synced/categories.yml)
• Updates platform table and feature cards spacing
• Adds a temp fix for pill buttons ( Forcing dynamic icon output instead of relying on :type prop )

Production	Review app
https://about.gitlab.com/platform/	https://3565-improve-behaviour-of-features-page-sub-links.about.gitlab-review.app/platform/
https://about.gitlab.com/features/	https://3565-improve-behaviour-of-features-page-sub-links.about.gitlab-review.app/features/

Step 2: Ensure that your changes comply with the following, where applicable:

• I, the Assignee, have run Axe tools on any updated pages, and fixed the relevant accessibility issues.
• These changes work on both Safari, Chrome, and Firefox.
• These changes have been reviewed for Visual Quality Assurance and Functional Quality Assurance on Mobile, Desktop, and Tablet.
• These changes work with our Google Analytics and SEO tools.
• These changes have been documented as expected.

Build Variables:

• Use Contentful Preview API

Closes #3565 (closed)