Fix only_full_group_by issue in permission processor query

[muzzwood]

What does it do?

Fixes an only_full_group_by issue in MODX\Revolution\Processors\Security\Access\Permission\GetList

Why is it needed?

So the permission combobox works when only_full_group_by is enabled.

How to test

Have only_full_group_by enabled in MySQL and try to select a permission on either the widget edit panel on the Dashboards page, or create a new permission in a policy template.

Related issue(s)/PR(s)

Resolves #16226