mail/exim: Unmark BROKEN for openssl30
New version 4.96 comes with support for OpenSSL 3.0.X which has been
tested however support with 3.1.X has not yet been tested.
It maybe the case that while I was marking ports BROKEN the MAINTAINER
was updating the port and missed this snippet causing a mid air
collission.
PR: 265098
Tested by: i.dani@outlook.com