feat(ui): restore sort by last updated date

[stevefulme1]

Summary

• Adds "Last updated" (updated_at) sort option to the collections search page sort dropdown
• Updates collection list item to prefer updated_at over pulp_created for the "Updated" date display when available
• Adds optional updated_at field to CollectionVersionSearch response type

Backend dependency

The frontend sort option sends order_by=updated_at to the v3/plugin/ansible/search/collection-versions/ API. The backend (pulp_ansible) must support this parameter for the sort to work. If updated_at is not yet exposed:

• The pulp_ansible search endpoint needs to include updated_at in the serializer
• The collections table should have an index on updated_at for performance

Ref: AAP-67527

Files changed

• src/components/collection-filter.ts — Added "Last updated" sort option
• src/api/response-types/collection.ts — Added optional updated_at field
• src/components/collection-list-item.tsx — Prefer updated_at for date display

Test plan

• Verify "Last updated" appears in the sort dropdown on collections page
• Verify sort works when backend supports order_by=updated_at
• Verify graceful fallback — list item shows pulp_created when updated_at is undefined
• Verify TypeScript compiles without errors (npm run lint:ts)

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