mail/exim: security update 4.96.1 -> 4.96.2 (+)

PR: 274501
MFH: 2023Q4
Security: CVE-2023-42117, CVE-2023-42119
Release notes: https://exim.org/static/doc/security/CVE-2023-zdi.txt

(cherry picked from commit bc760839a1f583cbaf6d1c4109fc8257e33082fe)