Show timestamp even if delivery doesnt fully succeed

[netthier]

When sending a message using "signal-cli -u 'xxx' send", the command usually returns a timestamp.
However, when sending a message to a group where at least one user has uninstalled Signal, the command returns "Failed to send message: Unregistered user 'xxx': null", instead of a timestamp.

All other members of the group still receive the message correctly though, so I see no reason for not printing out the timestamp.

[netthier]

More generally, an unregistered user shouldn't cause an error in my opinion, since the message still gets delivered correctly.
thread 'main' panicked at 'called Result::unwrap()on anErr value: D-Bus error: Unregistered user "xxx": null (org.asamk.Signal.Error.UnregisteredUser)'