Set comment visibility in JSON import

Context

A site administrator is importing a project full of issues into Jira using the JSON import wizard. The issues come from a system that supports internal comments so some of the imported comments need to be visible to staff only.

Problem

While the JSON import allows issues to have comments, they do not have any visibility property so we cannot mark comments as visible to staff group only.

Solution

Add a property to comments in JSON imports that sets the group visibility in Jira, so we can set internal comments as only visible to a specific group of users who are staff.

Workaround

Only alternative is to leave out the internal comments when generating the JSON for import, which means we lose content when moving issues to Jira.