We already include the issue title in the topic. But if one chooses
to group all gitlab notifications under one topic, the message body
is misleading in the sense that only the Issue ID and the description
are displayed, not the title, which isn't super helpful if the topic
doesn't tell you the title either.
I think we should err on the side of always including the title in
the main message body, which is what this commit does.
Fixes#9913.
67045d65a9