Allow Link Issues permission for users without agent license

Current Behaviour
A user must be a licensed agent in Jira Service Management in order to add a link from an issue in a Service Project to another issue.

• A user does not need an agent license to link from an issue in a Business or Software project to a Service Desk project. The link appears on both issues after being added.

"IGNORED_PERMISSIONS" list does not include LINK_ISSUES

Steps to reproduce the issue

1. Create a user with application access to Service Desk.
2. Create 2 Service Desk projects which share the same permission scheme.
3. Grant the user with the Service Desk Agent permission of one of the projects (project A). In the other project (project B), grant only Browse Projects, Create Issues and Link Issues permissions to the user.
   • This means that the user is an Agent of project A but not an Agent in project B.
4. As an Agent of the Service Desk project, use the Create Linked Issue option to create a linked issue in the other Service Desk project (project B) which the user is not an Agent.
5. Even though with the Create Issues and Link Issues permissions in the targeted project, the Agent will not be able to create the linked issue. However, the create issue and link issue operations can be performed separately.
   • Actual result: On the Create Linked Issue screen, an error You do not have permission to link issues in this project appears and the operation cannot be completed.

Suggested Change
Remove veto/override for LINK_ISSUES so that this permission in project permission scheme applies to all users and so that users who are not agents can see Add Link option on issues in Service Desk projects.