Follow-up correction for Bug 5462 - Fix variable names for template::toolkit

Follow-up correction for Bug 5462 - Fix variable names for template::toolkit

Previous commit modified checks for the item-level_itypes preference
to look for a different variable name but didn't update where that
variable is set in Auth.pm.

Other scripts perform a direct check of item-level_itypes and must
continue to use the name of the variable in the database.

Signed-off-by: Ian Walls <ian.walls@bywatersolutions.com>
Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>