Incorrect set of actions available for User directory resource in Audit log form filter

Problem description: In Reports => Audit log view, in case if filter field "Resource" is set to "User directory", then all of the Actions checkboxes are disabled, even though according to API documentation Add, Update and Delete actions can be executed for user directory object.

Steps to reproduce:

1. Navigate to Reports => Audit log
2. In filter form set field Resource to "User directory"
3. Check which of the Actions checkboxes are enabled.

Result: All Actions checkboxes are disabled.
Expected: At least "Add", "Update" and "Delete" actions should be available for User directory resource.