Parent Link and Team fields should be editable for users without Portfolio edit permission

We have restricted modify access to Portfolio to users who have attended training to ensure that there are no big data problems caused by users who don't know what they are doing (especially as there is no audit log in Portfolio).

However, this means they are now the only users who can set values in the Parent Link and Team fields in JIRA, which is causing a lot of confusion for our users as the fields are visible to all users.

We would like users who do not have permission to modify Portfolio plans to be able to set the values in these fields.