Component Lead should not permit users to be assigned that do not have the "Assignable user" permission

Summary

Jira will allow adding any user as Component Lead even if they have not any relation or access to the project.

Steps to Reproduce

1. Create a new user in the JIRA Internal directory
2. Remove from all groups and roles (ensure the user does not have Assignable user permission)
3. Confirm that you can still assign the user as a Component Lead in a project

Expected Results

Users should not be able to assign a user who does not have Assignable user permission (project or application access). A better user experience is to limit these users to those who have access.

Actual Results

Any user can be added as a Component Lead