Bug 1816311: Showing correct journal entry poster's name

When adding comment to the entry and the journal is owned by
group/institution

behatnotneeded

Change-Id: Id492c04e3facdbf00a5dfdc4d714c3c5103ff3a2
Signed-off-by: Robert Lyon <robertl@catalyst.net.nz>
(cherry picked from commit 5988b7de)