Bug 35215: Add few assumptions in Suggestions.t around emailing

Bug 35215: Add few assumptions in Suggestions.t around emailing

Test plan:
Without this patch, set pref ReplytoDefault or EmailAddressForSuggestions.
Run t/db_dependent/Suggestions.t (FAIL)
Fill branch email and reply for CPL branch.
Run t/db_dependent/Suggestions.t (FAIL: more errors)
Apply patch.
Run t/db_dependent/Suggestions.t (PASS)

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
(cherry picked from commit 0ea2a1c7be73995ca4b26c67f049912259c457a6)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>