Austenem/CAT-1020 Improve scroll tracking

[austenem]

Summary

Fixes scroll tracking on detail page table of contents so that processed dataset subsections are properly selected. Also adjusts scroll tracking to track the element closest to the middle of the page rather than the element at the top of the page.

Design Documentation/Original Tickets

CAT-1020 Jira ticket

Testing

Tested examples of entity detail pages with and without processed dataset sections.

Screenshots/Video

Local:

https://github.com/user-attachments/assets/553db1af-055c-425e-aab9-75f3d0c4f719

Prod:

https://github.com/user-attachments/assets/3e1f8614-ca1b-4c58-a55c-9a8abf4545dc

Checklist

• [X] Code follows the project's coding standards
  • [X] Lint checks pass locally
  • [X] New CHANGELOG-your-feature-name-here.md is present in the root directory, describing the change(s) in full sentences.
• [X] Unit tests covering the new feature have been added
• [X] All existing tests pass
• [X] Any relevant documentation in JIRA/Confluence has been updated to reflect the new feature
• [X] Any new functionalities have appropriate analytics functionalities added