Late signoff time delta not shown if less than a minute

[Gehock]

[18:44] @ Mention: User N. N. signed off from Apex Operation at 2020-07-18 18:45:00 role FSL before the operation.

[Gehock]

#43 has to be fixed first

[Gehock]

We're not using the late signoff mentions right now anyway, but this is still a bug that could be fixed.