test: add integration tests for local authority risks page

[J05h-L]

🧾 Summary

Adds integration test coverage for the Local Authority Risks page, validating the key behaviours.

AB#317736
AB#323974

✨ Feature Details

Functionality / Implementation:

Introduces integration tests that cover the core interactions and rendering responsibilities of the Risks page:

• Phase selection
• Pagination
• Table rendering, including presence of sortable table headers
• Back navigation

✅ Checklist

• Code follows project coding standards (e.g., Trunk-based guidelines, small PR size).
• Unit and integration tests added/updated (if applicable).
• Tested by running locally (or docs render correctly locally).
• Relevant documentation updated (if applicable).
• Screenshots or Demo included (for UI/frontend changes).

🔍 Notes

SortableTableHeaderCell already has comprehensive unit test coverage. Integration tests therefore only assert the presence and structure of sortable headers, with confidence that behavioural correctness is validated upstream.

This set of integration tests should fully exercise the behaviours required for the page, and no additional E2E coverage should be necessary.

[github-actions]

✅ All checks have passed!

Checklist

• Branch naming matches the standard (<category>/[<backlog-item>/][<task>-]description-in-kebab-case)
• Has at least one label attached
• Title matches Conventional Commits (<type>(<optional-scope>): <description>)
• Linked to an ADO ticket (contains AB#<ticket-number>)
• Markdown files pass linting