Setting ephemeral has to happen in an initial reply (reply() or
deferReply()) to set the mode for all replies in this 'thread'. Once the
ephemeral state of a message has been set it can not be changed. If you
want to send a visible message after an ephemeral message it has to be
new message. See https://discordjs.guide/slash-commands/response-methods.html#ephemeral-responses
