I have a LR MY coming next year, I'll have to look for this on the day I take delivery. Hopefully mine won't have this issue.
I had a 2016 Harley Davidson Road Glide which had water cooled heads, and for a few weeks before the water pump blew out on it the pump made a sound very similar to this. It was easy to hear because the pump is external on a motorcycle, I could even hear it over the sound of the engine and exhaust at idle. Harley eventually did a recall to replace the pumps because they were faulty and would fail prematurely, so if this Tesla sound is caused by a water pump then I'd wager its not a good thing for long term reliability.
Thank you for your posting, this is enlightening! And that's exactly what I am afraid of with these noisy water pumps. It is crazy that Tesla is ignoring this problem so much.