feat(api/v2): adjust quarantined ticket visibility

[wescopeland]

I changed my mind on a V2 API implementation detail.

Quarantined tickets are now exposed through the V2 API regardless of the consumer context. This makes the API consistent with the website UI.

[greptile-apps]

Greptile Summary

Exposes quarantined tickets to authenticated V2 API consumers, matching website visibility.

• Removes quarantine filtering from Ticket::visibleTo().
• Updates index coverage for non-manager consumers.

Confidence Score: 5/5

The PR appears safe to merge.

The visibility change matches the stated API behavior and existing website access.

_{Reviews (1): Last reviewed commit: "feat(api/v2): adjust quarantined ticket ..." | Re-trigger Greptile}