Bug 17944: QA follow-up

Bug 17944: QA follow-up

- Remove an unused use statement
- Fix pod
- Use snake_case
- Fix test "An itemtype cannot be deleted if and only if there is
biblioitem linked with it"

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
(cherry picked from commit 6d76f61a6b0b6b429246c5a9398ec55f97d98027)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>