Bug 30222: Further simplify logic

Bug 30222: Further simplify logic

For any borrower, we are either:
1 - following their preference, and that should set 'wants_email'
OR
2 - Never sending / following the cron, and can determine 'wants_email'
    from the 'send_notices' variable

This patch adds an 'else' if not using preferences to accomplish this

Follow test plan on previous patches

Signed-off-by: Andrew Fuerste-Henry <andrew@bywatersolutions.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>