John conroy/search last page

[john-conroy]

Summary

Phil noticed a bug scrolling through deeper search pages. The sort_after requires a unique tiebreaker.

From Phil:

The "see more results" stops working before it gets to the very end of the list of datasets (see snapshot where it stopped revealing more datasets)

Checklist

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