Bug 7733 - HidePatronName not working on moredetail

Bug 7733 - HidePatronName not working on moredetail

Patch implements HidePatronName system preference for 'Checkout status'
on moredetail (tab items from staff detail page).

Also adds some new 'if' statements, so 'Serial enumeration' and 'Paid for?' are
only shown when they are not empty.

Silences warns in the logs.

To test:
- Toggle system preference for an issued item and check name/cardnumber
are displayed correctly.
- Check serial enumeration and Paid for? show when not empty.

Signed-off-by: Nicole C. Engard <nengard@bywatersolutions.com>
Signed-off-by: Paul Poulain <paul.poulain@biblibre.com>