ARGO-5914: [API] Support editing incident and status descriptions

[irinaskop]

This PR adds support for editing both the incident description and the description associated with a specific incident status.

Two new endpoints are introduced:

• PATCH /v1/tenants/{id}/incidents/{incident-id}
  Updates the main description of an existing incident.

• PATCH /v1/tenants/{id}/incidents/{incident-id}/status/{status-id}
  Updates the status description associated with a specific incident status activity.

When the status description of the latest activity is edited, the incident's current status_description is also updated to keep the current incident state in sync.

Changes

• Add a new endpoint for updating an incident description.
• Add a new endpoint for updating a specific status description.
• Allow historical status descriptions to be corrected without creating a new status activity.
• Keep the incident's current status_description in sync when the latest status activity is edited.
• Add tests for both new endpoints.