The user can also edit the question after adding it.
The question in the poll can only be added/edited
by the user who started the poll.
The input bar will be disabled for the other users
if the question is not yet added. If the question is
added, the input bar will not be visible to the other
users.
This directly prevents a traceback when submessage events
arrive in the wrong order. This was probably a symptom
of not updating message.submessages for not-yet-widgeted
messages, which was fixed in an earlier commit, but we
want defensive code in case of races or other glitches, and
it's not the end of the world is somebody sees partial
survey results due to some corner case.
