Use the real discovery reply in the TD21 fixture. I said there that the TD21 doesn't answer UDP
discovery, and that was wrong: it was asleep during my first attempt,
and I had skipped discovery in `dump_devinfo` by passing the family
flags. The doorbell does answer, from port 20004.
This commit uses the real device response for the fixture, so the `_comment` marker is removed since
nothing in the fixture is hand-made any more.
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Co-authored-by: Smugaski <Smugaski@users.noreply.github.com>
d6e80d2c78