Bug 20144: [sql_modes] Set default value for marc_modification_template_actions

Bug 20144: [sql_modes] Set default value for marc_modification_template_actions

Cannot be empty strings.

Fix for:
Data truncated for column 'conditional'
Data truncated for column 'conditional_comparison'
Incorrect integer value: '' for column 'conditional_regex'

t/db_dependent/MarcModificationTemplates.t

Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Julian Maurice <julian.maurice@biblibre.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>