Bug 32815: Fix cataloguing/value_builder/callnumber.pl

Bug 32815: Fix cataloguing/value_builder/callnumber.pl

Use event parameter

This is part of the refactoring happening in bug 30975

Test plan:
1. Verify that the plugin continues to work as before

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
(cherry picked from commit aa726e5329cda74f78e97c6ce379cfba93ea26f4)
Signed-off-by: Jacob O'Mara <jacob.omara@ptfs-europe.com>
(cherry picked from commit 00fa18c944df65f3205e97a5a1603d043cf5717d)
Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>
(cherry picked from commit 91d9ec38a0350cef93f2b691e1f89f828f5ec5f5)
Signed-off-by: Arthur Suzuki <arthur.suzuki@biblibre.com>