message: fix(test): add check of dm message exist
diff: @@ -7,5 +7,6 @@ Deno.test("[member] get dm channel and send a message", async () => {
  const channel = await bot.helpers.getDmChannel(750661528360845322n);
  assertExists(channel?.id);
  - await bot.helpers.sendMessage(channel.id, { content: "https://i.imgur.com/doG55NR.png" });
  + const message = await bot.helpers.sendMessage(channel.id, { content: "https://i.imgur.com/doG55NR.png" });
  + assertExists(message?.content);
  });
  