Bug 32826: Fix cataloguing/value_builder/unimarc_field_106.pl

Bug 32826: Fix cataloguing/value_builder/unimarc_field_106.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 6c948b933e3991bc8ec17022cf87ad4e37ce1dd2)
Signed-off-by: Matt Blenkinsop <matt.blenkinsop@ptfs-europe.com>
(cherry picked from commit 351fda3f05416e0558e61a1248b85eb57774bd05)

Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>
(cherry picked from commit c8f2dbc4bc73aa8b52249acb4e5578a07feec66a)
Signed-off-by: Arthur Suzuki <arthur.suzuki@biblibre.com>